Table of Contents

Chapter 1 IPv6 Configuration. 1-1

1.1 IPv6 Overview. 1-1

1.1.1 IPv6 Features. 1-2

1.1.2 Introduction to IPv6 Address. 1-3

1.1.3 Dual Stack Overview. 1-7

1.1.4 Introduction to IPv6 Neighbor Discovery Protocol 1-7

1.1.5 IPv6 PMTU Discovery. 1-10

1.1.6 Introduction to IPv6 DNS. 1-11

1.1.7 Protocol Specifications. 1-12

1.2 Configuring Basic IPv6 Functions. 1-12

1.2.1 Configuring the IPv6 Packet Forwarding Function. 1-12

1.2.2 Configuring an IPv6 Unicast Address. 1-12

1.3 Configuring IPv6 NDP. 1-14

1.3.1 Configuring a Static Neighbor Entry. 1-14

1.3.2 Configuring the Maximum Number of Neighbors Dynamically Learned. 1-15

1.3.3 Configuring Parameters Related to an RA Message. 1-15

1.3.4 Configuring the Attempts to Send an NS Message for Duplicate Address Detection. 1-18

1.4 Configuring PMTU Discovery. 1-19

1.4.1 Configuring a Static PMTU for a Specified IPv6 Address. 1-19

1.4.2 Configuring the Aging Time for PMTU. 1-19

1.5 Configuring IPv6 TCP Properties. 1-19

1.6 Configuring the Maximum Number of IPv6 ICMP Error Packets Sent within a Specified Time. 1-20

1.7 Configuring IPv6 DNS. 1-21

1.7.1 Configuring Static IPv6 DNS. 1-21

1.7.2 Configuring Dynamic IPv6 DNS. 1-21

1.8 Displaying and Maintaining IPv6. 1-22

1.9 IPv6 Configuration Example. 1-24

Chapter 2 IPv6 Application Configuration. 2-1

2.1 Introduction to IPv6 Application. 2-1

2.2 Ping IPv6. 2-1

2.3 Traceroute IPv6. 2-1

2.4 FTP Configuration. 2-2

2.4.1 Configuration Prerequisites. 2-3

2.4.2 Logging in to the FTP Server 2-3

2.5 TFTP Configuration. 2-4

2.5.1 Configuration Preparation. 2-4

2.5.2 TFTP Configuration. 2-4

2.6 IPv6 Telnet 2-5

2.6.1 Configuration Prerequisites. 2-5

2.6.2 Setting up IPv6 Telnet Connections. 2-5

2.6.3 Displaying and Maintaining IPv6 Telnet 2-6

2.7 Examples of Typical IPv6 Application Configurations. 2-6

2.7.1 Network requirements. 2-6

2.7.2 Network diagram.. 2-6

2.7.3 Configuration procedure. 2-7

2.8 Troubleshooting IPv6 Application. 2-8

2.8.1 Unable to Ping a Remote Destination. 2-8

2.8.2 Unable to Run Traceroute. 2-8

2.8.3 Unable to Run FTP. 2-9

2.8.4 Unable to Run TFTP. 2-9

2.8.5 Unable to Run Telnet 2-9

 

Chapter 1  IPv6 Configuration

 

 

When configuring IPv6, go to these sections for information you are interested in:

l           IPv6 Overview

l           Configuring Basic IPv6 Functions

l           Configuring IPv6 NDP

l           Configuring PMTU Discovery

l           Configuring IPv6 TCP Properties

l           Configuring the Maximum Number of IPv6 ICMP Error Packets Sent within a Specified Time

l           Configuring IPv6 DNS

l           Displaying and Maintaining IPv6

l           IPv6 Configuration Example

1.1  IPv6 Overview

Internet protocol version 6 (IPv6), also called IP next generation (IPng), was designed by the Internet Engineering Task Force (IETF) as the successor to Internet protocol version 4 (IPv4).The significant difference between IPv6 and IPv4 is that IPv6 increases the IP address size from 32 bits to 128 bits. This section covers the following sections:

l           IPv6 Features

l           Introduction to IPv6 Address

l           Dual Stack Overview

l           Introduction to IPv6 Neighbor Discovery Protocol

l           IPv6 PMTU Discovery

l           Introduction to IPv6 DNS

l           Protocol Specifications

1.1.1  IPv6 Features

I. Header format simplification

IPv6 cuts down some IPv4 header fields or move them to extension headers to reduce the load of basic IPv6 headers, thus making IPv6 packet handling simple and improving the forwarding efficiency. Although the IPv6 address size is four times that of IPv4 addresses, the size of basic IPv6 headers is only twice that of IPv4 headers (excluding the Options field).

Figure 1-1 Comparison between IPv4 header format and IPv6 header format

II. Adequate address space

The source IPv6 address and the destination IPv6 address are both 128 bits (16 bytes) long.IPv6 can provide 3.4 x 10³⁸ addresses to completely meet the requirements of hierarchical address division as well as allocation of public and private addresses.

III. Hierarchical address structure

IPv6 adopts the hierarchical address structure to quicken route search and reduce the system source occupied by the IPv6 routing table by means of route aggregation.

IV. Automatic address configuration

To simplify the host configuration, IPv6 supports stateful address configuration and stateless address configuration. Stateful address configuration means that a host acquires an IPv6 address and related information from the server (for example, DHCP server). Stateless address configuration means that the host automatically configures an IPv6 address and related information based on its own link-layer address and the prefix information issued by the router. In addition, a host can generate a link-local address based on its own link-layer address and the default prefix (FE80::/64) to communicate with other hosts on the link.

V. Built-in security

IPv6 uses IPSec as its standard extension header to provide end-to-end security. This feature provides a standard for network security solutions and improves the interoperability between different IPv6 applications.

VI. Support for QoS

The Flow Label field in the IPv6 header allows the device to label packets in a flow and provide special handling for these packets.

VII. Enhanced neighbor discovery mechanism

The IPv6 neighbor discovery protocol means a group of Internet control message protocol version 6 (ICMPv6) messages manages the interaction between neighbor nodes (nodes on the same link).The group of ICMPv6 messages takes the place of address resolution protocol (ARP), Internet control message protocol version 4 (ICMPv4), and ICMPv4 redirection messages to provide a series of other functions.

VIII. Flexible extension headers

IPv6 cancels the Options field in IPv4 packets but introduces multiple extension headers. In this way, IPv6 enhances the flexibility greatly to provide scalability for IP while improving the processing efficiency. The Options field in IPv4 packets contains only 40 bytes, while the size of IPv6 extension headers is restricted by that of IPv6 packets.

1.1.2  Introduction to IPv6 Address

I. IPv6 address format

An IPv6 address is represented as a series of 16-bit hexadecimals, separated by colons. An IPv6 address is divided into eight groups, 16 bits of each group are represented by four hexadecimal numbers which are separated by colons, for example, 2001:0000:130F:0000:0000:09C0:876A:130B.

To simplify the representation of IPv6 addresses, zeros in IPv6 addresses can be handled as follows:

l           Leading zeros in each group can be removed. For example, the above-mentioned address can be represented in shorter format as 2001:0:130F:0:0:9C0:876A:130B.

l           If an IPv6 address contains two or more consecutive groups of zeros, they can replaced by the double-colon :: option. For example, the above-mentioned address can be represented in the shortest format as 2001:0:130F::9C0:876A:130B.

 

 

An IPv6 address consists of two parts: address prefix and interface ID. The address prefix and the interface ID are respectively equivalent to the network ID to the host ID in an IPv4 address.

An IPv6 address prefix is written in IPv6-address/prefix-length notation, where IPv6-address is an IPv6 address in any of the notations and prefix-length is a decimal number indicating how many bits from the utmost left of an IPv6 address are the address prefix.

II. IPv6 address classification

IPv6 addresses mainly fall into three types: unicast address, multicast address and anycast address.

l           Unicast address: An identifier for a single interface, similar to an IPv4 unicast address .A packet sent to a unicast address is delivered to the interface identified by that address.

l           Multicast address: An identifier for a set of interfaces (typically belonging to different nodes), similar to an IPv4 multicast address. A packet sent to a multicast address is delivered to all interfaces identified by that address.

l           Anycast address: An identifier for a set of interfaces (typically belonging to different nodes).A packet sent to an anycast address is delivered to one the interfaces identified by that address (the nearest one, according to the routing protocols’ measure of distance).

 

 

The type of an IPv6 address is designated by the first several bits called format prefix. Table 1-1 lists the mapping between major address types and format prefixes.

Table 1-1 Mapping between address types and format prefixes

Type		Format prefix (binary)	IPv6 prefix ID
Unicast address	Unassigned address	00...0  (128 bits)	::/128
	Loopback address	00...1  (128 bits)	::1/128
	Link-local address	1111111010	FE80::/10
	Site-local address	1111111011	FEC0::/10
	Global unicast address	other forms	—
Multicast address		11111111	FF00::/8
Anycast address		Anycast addresses are taken from unicast address space and are not syntactically distinguishable from unicast addresses.

 

III. Unicast address

There are several forms of unicast address assignment in IPv6, including aggregatable global unicast address, link-local address, and site-local address.

l           The aggregatable global unicast address, equivalent to an IPv4 public address, is used for aggregatable links and provided for network service providers. The structure of such a type of address allows efficient routing aggregation to restrict the number of global routing entries.

l           The link-local address is used for communication between link-local nodes in neighbor discovery and stateless autoconfiguration. Routers must not forward any packets with link-local source or destination addresses to other links.

l           IPv6 unicast site-local addresses are similar to private IPv4 addresses. Routers must not forward any packets with site-local source or destination addresses outside of the site (equivalent to a private network).

l           Loopback address: The unicast address 0:0:0:0:0:0:0:1 (represented in shorter format as ::1) is called the loopback address and may never be assigned to any physical interface. Like the loopback address in IPv4, it may be used by a node to send an IPv6 packet to itself.

l           Unassigned address: The unicast address :: is called the unassigned address and may not be assigned to any node. Before acquiring a valid IPv6 address, a node may fill this address in the source address field of an IPv6 packet, but may not use it as a destination IPv6 address.

IV. Multicast address

Multicast addresses listed in Table 1-2 are reserved for special purpose.

Table 1-2 Reserved IPv6 multicast addresses

Address	Application
FF01::1	Node-local scope all-nodes multicast address
FF02::1	Link-local scope all-nodes multicast address
FF01::2	Node-local scope all-routers multicast address
FF02::2	Link-local scope all-routers multicast address
FF05::2	Site-local scope all-routers multicast address

 

Besides, there is another type of multicast address: solicited-node address. The solicited-node multicast address is used to acquire the link-layer addresses of neighbor nodes on the same link and is also used for duplicate address detection. Each IPv6 unicast or anycast address has one corresponding solicited-node address. The format of a solicited-node multicast address is as follows:

FF02:0:0:0:0:1:FFXX:XXXX

Where, FF02:0:0:0:0:1:FF is permanent and consists of 104 bits, and XX:XXXX is the last 24 bits of an IPv6 address.

V. Interface identifier in IEEE EUI-64 format

Interface identifiers in IPv6 unicast addresses are used to identify interfaces on a link and they are required to be unique on that link. Interface identifiers in IPv6 unicast addresses are currently required to be 64 bits long. An interface identifier is derived from the link-layer address of that interface. Interface identifiers in IPv6 addresses are 64 bits long, while MAC addresses are 48 bits long. Therefore, the hexadecimal number FFFE needs to be inserted in the middle of MAC addresses (behind the 24 high-order bits).To ensure the interface identifier obtained from a MAC address is unique, it is necessary to set the universal/local (U/L) bit (the seventh high-order bit) to “1”.Thus, an interface identifier in EUI-64 format is obtained.

Figure 1-2 Convert a MAC address into an EUI-64 address

1.1.3  Dual Stack Overview

A network node that supports both IPv4 and IPv6 is called a dual stack node. A dual stack node configured with an IPv4 and an IPv6 addresses can have both IPv4 and IPv6 packets transmitted.

For an upper layer application supporting both IPv4 and IPv6, either TCP or UDP can be selected at the transport layer, while at network layer, IPv6 stack is peferred. Figure 1-3 illustrates the IPv4/IPv6 dual stack in relation to the IPv4 stack.

Figure 1-3 IPv4/IPv6 dual stack in relation to IPv4 Stack

1.1.4  Introduction to IPv6 Neighbor Discovery Protocol

The IPv6 neighbor discovery protocol (NDP) uses five types of ICMPv6 messages to implement the following functions:

l           Address resolution

l           Neighbor unreachability detection

l           Duplicate address detection

l           Router/prefix discovery and address autoconfiguration

l           Redirection

Table 1-3 lists the types and functions of ICMPv6 messages used by the NDP.

Table 1-3 Types and functions of ICMPv6 messages

ICMPv6 message	Function
Neighbor solicitation (NS) message	Used to acquire the link-layer address of a neighbor
	Used to verify whether the neighbor is reachable
	Used to perform a duplicate address detection
Neighbor advertisement (NA) message	Used to respond to a neighbor solicitation message
	When the link layer changes, the local node initiates a neighbor advertisement message to notify neighbor nodes of the node information change.
Router solicitation (RS) message	After started, a host sends a router solicitation message to request the router for an address prefix and other configuration information for the purpose of autoconfiguration.
Router advertisement (RA) message	Used to respond to a router solicitation message
	With the RA message suppression disabled, the router regularly sends a router advertisement message containing information such as address prefix and flag bits
Redirect message	When a certain condition is satisfied, the default gateway sends a redirect message to the source host so that the host can reselect a correct next hop router to forward packets.

 

The NDP mainly provides the following functions:

I. Address resolution

Similar to the ARP function in IPv4, a node acquires the link-layer address of neighbor nodes on the same link through NS and NA messages. Figure 1-4 shows how node A acquires the link-layer address of node B.

Figure 1-4 Address resolution

The address resolution procedure is as follows:

1)         Node A multicasts an NS message. The source address of the NS message is the IPv6 address for the interface of node A and the destination address is the solicited-node multicast address of node B. The NS message contains the link-layer address of node A.

2)         After receiving the NS message, node B judges whether the destination address of the packet is the corresponding solicited-node multicast address of its own IPv6 address. If yes, node B returns an NA message containing the link-layer address of node B.

3)         Node A acquires the link-layer address of node B fro the NA message. After that, node A and node B can communicate.

II. Neighbor unreachability detection

After node A acquires the link-layer address of its neighbor node B, node A can verify whether node B is reachable according to NS and NA messages.

1)         Node A sends an NS message whose destination address is the IPv6 address of node B.

2)         If node A receives an NA message from node B, node A considers that node B is reachable. Otherwise, node B is unreachable.

III. Duplicate address detection

After node A acquires an IPv6 address, it should perform the duplicate address detection to determine whether the address is being used by other nodes (similar to the gratuitous ARP function).The duplication address detection is accomplished through NS and NA messages. Figure shows the duplicate address detection procedure.

Figure 1-5 Duplicate address detection

The duplicate address detection procedure is as follows:

1)         Node A sends an NS message whose source address is the unassigned address :: and destination address is the corresponding solicited-node multicast address of the IPv6 address to be detected. The NS message contains the IPv6 address.

2)         If node B uses this IPv6 address, node B returns an NA message. The NA message contains the IPv6 address of node B.

3)         Node A learns that the IPv6 address is being used by node B after receiving the NA message from node B. Otherwise, node B is not using the IPv6 address and node A can use it.

IV. Router/prefix discovery and address autoconfiguration

Router/prefix discovery means that a host acquires the neighbor router, the prefix of the network where the router is located, and other configuration parameters from the received RA message.

Stateless address autoconfiguration means that a host automatically configure an IPv6 address according to the information obtained through router/prefix discovery.

The router/prefix discovery and address autoconfiguration is implemented through RS and RA messages. The router/prefix discovery and address autoconfiguration procedure is as follows:

1)         After started, a host sends an RS message to request the router for the address prefix and other configuration information for the purpose of autoconfiguration.

2)         The router returns an RA message containing information such as address prefix and flag bits. (The router also regularly sends an RA message.)

3)         The host automatically configures an IPv6 address and other information for its interface according to the address prefix and other configuration parameters in the RA message.

V. Redirection

When a host is started, its routing table may contain only the default route to the gateway. When certain conditions are satisfied, the gateway sends an ICMPv6 redirect message to the source host so that the host can select a better next hop router to forward packets (similar to the ICMP redirection function in IPv4).

The gateway will send an IPv6 ICMP redirect message when the following conditions are satisfied:

l           The receiving interface and the forwarding interface are the same.

l           The selected route itself is not created or modified by an IPv6 ICMP redirect message.

l           The selected route is not the default route.

l           The forwarded IPv6 packet does not contain any extension header carrying the routing information of intermediate nodes on the forwarding path.

1.1.5  IPv6 PMTU Discovery

The links that a packet passes from the source to the destination may have different MTUs. In IPv6, when the packet size exceeds the MTU of a link, the packet will be fragmented at the source so as to reduce the processing pressure of the forwarding device and utilize network resources rationally.

The path MTU (PMTU) discovery mechanism is to find the minimum MTU on the path from the source to the destination. Figure 1-6 shows the working procedure of the PMTU discovery.

Figure 1-6 Working procedure of the PMTU discovery

The working procedure of the PMTU discovery is as follows:

1)         The source host uses its MTU to fragment packets and then sends them to the destination host.

2)         If the MTU supported by the packet forwarding interface is less than the size of a packet, the forwarding device will discard the packet and return an ICMPv6 error packet containing the interface MTU to the source host.

3)         After receiving the ICMPv6 error packet, the source host uses the returned MTU to fragment the packet again and then sends it.

4)         Step 2 to step 3 are repeated until the destination host receives the packet. In this way, the minimum MTU on the path from the source host to the destination host is determined.

1.1.6  Introduction to IPv6 DNS

In the IPv6 network, a domain name system (DNS) supporting IPv6 converts domain names into IPv6 addresses. Different from an IPv4 DNS, an IPv6 DNS converts domain names into IPv6 addresses, instead of IPv4 addresses.

However, just like an IPv4 DNS, an IPv6 DNS also covers static domain name resolution and dynamic domain name resolution. The function and implementation of these two types of domain name resolution are the same as those of an IPv4 DNS. For details, refer to DNS module.

Usually, the DNS server connecting IPv4 and IPv6 networks contain not only A records (IPv4 addresses) but also AAAA records (IPv6 addresses). The DNS server can convert domain names into IPv4 addresses or IPv6 addresses. In this way, the DNS server has the functions of both IPv6 DNS and IPv4 DNS.

1.1.7  Protocol Specifications

Protocol specifications related to IPv6 include:

l           RFC 1881: IPv6 Address Allocation Management

l           RFC 1887: An Architecture for IPv6 Unicast Address Allocation

l           RFC 1981: Path MTU Discovery for IP version 6

l           RFC 2375: IPv6 Multicast Address Assignments

l           RFC 2460: Internet Protocol, Version 6 (IPv6) Specification.

l           RFC 2461: Neighbor Discovery for IP Version 6 (IPv6)

l           RFC 2462: IPv6 Stateless Address Autoconfiguration

l           RFC 2463: Internet Control Message Protocol (ICMPv6) for the Internet Protocol Version 6 (IPv6) Specification

l           RFC 2464: Transmission of IPv6 Packets over Ethernet Networks

l           RFC 2526: Reserved IPv6 Subnet Anycast Addresses

l           RFC 3307: Allocation Guidelines for IPv6 Multicast Addresses

l           RFC 3513: Internet Protocol Version 6 (IPv6) Addressing Architecture

l           RFC 3596: DNS Extensions to Support IP Version 6

1.2  Configuring Basic IPv6 Functions

1.2.1  Configuring the IPv6 Packet Forwarding Function

Before IPv6-related configurations, you must enable the IPv6 packet forwarding function for an interface. Otherwise, the interface cannot forward IPv6 packets even if an IPv6 address is configured, resulting in interworking failures in the IPv6 network.

Follow these steps to configure the IPv6 packet forwarding function:

To do...	Use the command...	Remarks
Enter system view	system-view	—
Enable the IPv6 packet forwarding function	ipv6	Required Disabled by default.

 

1.2.2  Configuring an IPv6 Unicast Address

IPv6 site-local addresses and aggregatable global unicast addresses can be configured in either of the following ways:

l           EUI-64 format: When the EUI-64 format is adopted to form IPv6 addresses, the IPv6 address prefix of an interface is the configured prefix and the interface identifier is derived from the link-layer address of the interface.

l           Manual configuration: IPv6 site-local addresses or aggregatable global unicast addresses are configured manually.

IPv6 link-local addresses can be acquired in either of the following ways:

l           Automatic generation: The device automatically generates a link-local address for an interface according to the link-local address prefix (FE80::/64) and the link-layer address of the interface.

l           Manual assignment: IPv6 link-local addresses can be assigned manually.

Follow these steps to configure an IPv6 unicast address:

To do...		Use the command...	Remarks
Enter system view		system-view	—
Enter interface view		interface interface-type interface-number	—
Configure an IPv6 aggregatable global unicast address or site-local address	Manually assign an IPv6 address	ipv6 address { ipv6-address prefix-length | ipv6-address/prefix-length }	Alternative By default, no site-local address or aggregatable global unicast address is configured for an interface. Note that the prefix length specified by the prefix-length argument cannot be greater than 64.
	Adopt the EUI-64 format to form an IPv6 address	ipv6 address ipv6-address/prefix-length eui-64
Configure an IPv6 link-local address	Automatically generate a link-local address	ipv6 address auto link-local	Optional By default, after an IPv6 site-local address or aggregatable global unicast address is configured for an interface, a link-local address will be generated automatically.
	Manually assign a link-local address for an interface.	ipv6 address ipv6-address link-local

 

 

1.3  Configuring IPv6 NDP

1.3.1  Configuring a Static Neighbor Entry

The IPv6 address of a neighbor node can be resolved into a link-layer address dynamically through NS and NA messages or statically through manual configuration.

The device uniquely identifies a static neighbor entry according to the IPv6 address and the layer 3 interface ID.

Configure the corresponding IPv6 address and link-layer address for a layer 3 interface.

Follow these steps to configure a static neighbor entry:

To do...	Use the command...	Remarks
Enter system view	system-view	—
Configure a static neighbor entry	ipv6 neighbor ipv6-address mac-address { vlan-id port-type port-number | interface interface-type interface-number }	Required

 

1.3.2  Configuring the Maximum Number of Neighbors Dynamically Learned

The device can dynamically acquire the link-layer address of a neighbor node through NS and NA messages. Too large a neighbor table from which neighbor entries can be dynamically acquired may lead to the forwarding performance degradation of the device. Therefore, you can restrict the size of the neighbor table by setting the maximum number of neighbors that an interface can dynamically learn. When the number of dynamically learned neighbors reaches the threshold, the interface will stop learning neighbor information.

Follow these steps to configure the maximum number of neighbors dynamically learned:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter interface view	interface interface-type interface-number	—
Configure the maximum number of neighbors dynamically learned by an interface	ipv6 neighbors max-learning-num number	Optional The default value is 1024

 

1.3.3  Configuring Parameters Related to an RA Message

You can configure whether the interface sends an RA message, the interval for sending RA messages, and parameters in RA messages. After receiving an RA message, a host can use these parameters to perform corresponding operations. Table 1-4 lists the configurable parameters in an RA message and their descriptions.

Table 1-4 Parameters in an RA message and their descriptions

Parameters	Description
Cur hop limit	When sending an IPv6 packet, a host uses the value of this parameter to fill the Hop Limit field in IPv6 headers. Meanwhile, the value of this parameter is equal to the value of the Cur Hop Limit field in response messages of the device.
Prefix information options	After receiving the prefix information, the hosts on the same link can perform stateless autoconfiguration operations.
M flag	This field determines whether hosts use the stateful autoconfiguration to acquire IPv6 addresses. If the M flag is set to 1, hosts use the stateful autoconfiguration to acquire IPv6 addresses. Otherwise, hosts use the stateless autoconfiguration to acquire IPv6 addresses, that is, hosts configure IPv6 addresses according to their own link-layer addresses and the prefix information issued by the router.
O flag	This field determines whether hosts use the stateful autoconfiguration to acquire information other than IPv6 addresses. If the O flag is set to 1, hosts use the stateful autoconfiguration (for example, DHCP server) to acquire information other than IPv6 addresses. Otherwise, hosts use the stateless autoconfiguration to acquire information other than IPv6 addresses.
Router lifetime	This field is used to set the lifetime of the router that sends RA messages to serve as the default router of hosts. According to the router lifetime in the received RA messages, hosts determine whether the router sending RA messages can serve as the default router of hosts.
Retrans timer	If a node fails to receive a response message within the specified time after sending an NS message, the node will retransmit it.
Reachable time	After the neighbor unreachability detection shows that a neighbor is reachable, a node considers the neighbor is reachable within the reachable time. If the node needs to send a packet to a neighbor after the reachable time expires, the node will again confirm whether the neighbor is reachable.

 

 

Follow these steps to configure parameters related to an RA message:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Configure the current hop limit	ipv6 nd hop-limit value	Optional 64 by default.
Enter interface view	interface interface-type interface-number	—
Disable the RA message suppression.	undo ipv6 nd ra halt	Optional By default, RA messages are suppressed.
Configure the interval for sending RA messages	ipv6 nd ra interval max-interval-value min-interval-value	Optional By default, the maximum interval for sending RA messages is 600 seconds, and the minimum interval is 200 seconds. The device sends RA messages at intervals of a random value between the maximum interval and the minimum interval. The minimum interval should be less than or equal to 0.75 times the maximum interval.
Configure the prefix information options in RA messages	ipv6 nd ra prefix { ipv6-address prefix-length | ipv6-address/prefix-length } valid-lifetime preferred-lifetime [ no-autoconfig | off-link ]*	Optional By default, no prefix information is configured in RA messages and the IPv6 address of the interface sending RA messages is used as the prefix information.
Set the M flag to 1	ipv6 nd autoconfig managed-address-flag	Optional By default, the M flag bit is set to 0, that is, hosts acquire IPv6 addresses through stateless autoconfiguration.
Set the O flag bit to 1.	ipv6 nd autoconfig other-flag	Optional By default, the O flag bit is set to 0, that is, hosts acquire other information through stateless autoconfiguration.
Configure the router lifetime in RA messages	ipv6 nd ra router-lifetime value	Optional 1,800 seconds by default.
Set the retrans timer	ipv6 nd ns retrans-timer value	Optional By default, the local interface sends NS messages at intervals of 1,000 milliseconds and the Retrans Timer field in RA messages sent by the local interface is equal to 0.
Set the reachable time	ipv6 nd nud reachable-time value	Optional By default, the neighbor reachable time on the local interface is 30,000 milliseconds and the Reachable Timer field in RA messages is 0.

 

 

1.3.4  Configuring the Attempts to Send an NS Message for Duplicate Address Detection

The device sends a neighbor solicitation (NS) message for duplicate address detection. If the device does not receive a response within a specified time (set by the ipv6 nd ns retrans-timer value command), the device continues to send an NS message. If the device still does not receive a response after the number of attempts to send an NS message reaches the maximum, the device judges the acquired address is available

Follow these steps to configure the attempts to send an NS message for duplicate address detection:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter interface view	interface interface-type interface-number	—
Configure the attempts to send an NS message for duplicate address detection	ipv6 nd dad attempts value	Optional 1 by default. When the value argument is set to 0, the duplicate address detection is disabled.

 

1.4  Configuring PMTU Discovery

1.4.1  Configuring a Static PMTU for a Specified IPv6 Address

You can configure a static PMTU for a specified IPv6 address. When forwarding packets, an interface compares the MTU of the interface with the static PMTU of the specified destination IPv6 address, and uses the smaller one to fragment packets.

Follow these steps to configure a static PMTU for a specified address:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Configure a static PMTU for a specified IPv6 address	ipv6 pathmtu ipv6-address [ value ]	Required By default, no static PMTU is configured.

 

1.4.2  Configuring the Aging Time for PMTU

After the MTU of the path from the source host to the destination host is dynamically determined, the source host uses this MTU to send subsequent packets to the destination host. After the aging time expires, the dynamically determined PMTU is deleted and the source host re-determines the MTU to send packets according to the PMTU mechanism.

The aging time is invalid for static PMTU.

Follow these steps to configure the aging time for PMTU:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Configure the aging time for PMTU	ipv6 pathmtu age age-time	Optional 10  minutes by default.

 

1.5  Configuring IPv6 TCP Properties

The IPv6 TCP properties you can configure include:

l           synwait timer: When a SYN packet is sent, the synwait timer is triggered. If no response packet is received before the synwait timer expires, the IPv6 TCP connection establishment fails.

l           finwait timer: When the IPv6 TCP connection status is FIN_WAIT_2, the finwait timer is triggered. If no packet is received before the finwait timer expires, the IPv6 TCP connection is terminated. If FIN packets are received, the IPv6 TCP connection status becomes TIME_WAIT. If other packets are received, the finwait timer is reset from the last packet and the connection is terminated after the finwait timer expires.

l           Size of the IPv6 TCP buffer.

Follow these steps to configure IPv6 TCP properties:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Set the finwait timer of IPv6 TCP packets	tcp ipv6 timer fin-timeout wait-time	Optional 675 seconds by default
Set the synwait timer of IPv6 TCP packets	tcp ipv6 timer syn-timeout wait-time	Optional 75 seconds by default
Set the size of the IPv6 TCP buffer	tcp ipv6 window size	Optional 8 KB by default

 

1.6  Configuring the Maximum Number of IPv6 ICMP Error Packets Sent within a Specified Time

If too many IPv6 ICMP error packets are sent within a short time in a network, network congestion may occur. To avoid network congestion, you can control the maximum number of IPv6 ICMP error packets sent within a specified time. Currently, the token bucket algorithm is adopted.

You can set the capacity of a token bucket, namely, the number of tokens in the bucket. In addition, you can set the update period of the token bucket, namely, the interval for updating the number of tokens in the token bucket to the configured capacity. One token allows one IPv6 ICMP error packet to be sent. Each time an IPv6 ICMP error packet is sent, the number of tokens in a token bucket decreases by 1.If the number of IPv6 ICMP error packets successively sent exceeds the capacity of the token bucket, the subsequent IPv6 ICMP error packets cannot be sent out until the number of tokens in the token bucket is updated and new tokens are added to the bucket.

Follow these steps to configure the maximum number of IPv6 ICMP error packets sent within a specified time:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Configure the capacity of the token bucket controlling the number of IPv6 ICMP error packets sent within a specified time as well as the update period	ipv6 icmp-error { bucket bucket-size | ratelimit interval }*	Optional By default, the capacity of a token bucket is 10 and the update period to 100 milliseconds. That is, at most 10 IPv6 ICMP error packets can be sent within 100 milliseconds.

 

1.7  Configuring IPv6 DNS

1.7.1  Configuring Static IPv6 DNS

You can establish the mapping between host name and IPv6 address through the following configuration. You can directly use a host name when applying telnet applications and the system will resolve the host name into an IPv6 address. Each host name can correspond to one IPv6 address at most.

Follow these steps to configure a host name and the corresponding IPv6 address:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Configure a host name and the corresponding IPv6 address	ipv6 host hostname ipv6-address	Required

 

1.7.2  Configuring Dynamic IPv6 DNS

If you want to use the dynamic domain name function, you can use the following command to enable the dynamic domain name resolution function. In addition, you should configure a DNS server so that a query request message can be sent to the correct server for resolution. The system can support at most six DNS servers.

You can configure a domain name suffix so that you only need to enter some fields of a domain name and the system automatically adds the preset suffix for address resolution. The system can support at most 10 domain name suffixes.

Follow these steps to configure dynamic IPv6 DNS:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enable the dynamic domain name resolution function	dns resolve	Required Disabled by default.
Configure an IPv6 DNS server	dns server ipv6 ipv6-address [ interface-type interface-number ]	Required
Configure the domain suffix.	dns domain domain-name	Required By default, no domain name suffix is configured, that is, the domain name is resolved according to the input information.

 

 

1.8  Displaying and Maintaining IPv6

To do…	Use the command…	Remarks
Display DNS domain name suffix information	display dns domain [ dynamic ]	Any view
Display IPv6 dynamic domain name cache information.	display dns ipv6 dynamic-host	Any view
Display DNS server information	display dns server [ dynamic ]	Any view
Display the FIB entries	display ipv6 fib [ ipv6-address ]	Any view
Display the mapping between host name and IPv6 address	display ipv6 host	Any view
Display the brief IPv6 information of an interface	display ipv6 interface [ interface-type interface-number | brief ]	Any view
Display neighbor information	display ipv6 neighbors [ ipv6-address | all | dynamic | interface interface-type interface-number | static | vlan vlan-id ] [ | { begin | exclude | include } text ]	Any view
Display the total number of neighbor entries satisfying the specified conditions	display ipv6 neighbors { all | dynamic | static | interface interface-type interface-number | vlan vlan-id } count	Any view
Display the PMTU information of an IPv6 address	display ipv6 pathmtu { ipv6-address | all | dynamic | static }	Any view
Display information related to a specified socket	display ipv6 socket [ socktype socket-type ] [ task-id socket-id ]	Any view
Display the statistics of IPv6 packets and IPv6 ICMP packets	display ipv6 statistics	Any view
Display the statistics of IPv6 TCP packets	display tcp ipv6 statistics	Any view
Display the IPv6 TCP connection status	display tcp ipv6 status	Any view
Display the statistics of IPv6 UDP packets	display udp ipv6 statistics	Any view
Clear IPv6 dynamic domain name cache information	reset dns ipv6 dynamic-host	In user view
Clear IPv6 neighbor information	reset ipv6 neighbors [ all | dynamic | interface interface-type interface-number | static ]	In user view
Clear the corresponding PMTU	reset ipv6 pathmtu { all | static | dynamic}	In user view
Clear the statistics of IPv6 packets	reset ipv6 statistics	In user view
Clear the statistics of all IPv6 TCP packets	reset tcp ipv6 statistics	In user view
Clear the statistics of all IPv6 UDP packets	reset udp ipv6 statistics	In user view

 

 

1.9  IPv6 Configuration Example

I. Network requirements

Two switches are directly connected through two GigabitEthernet ports. The GigabitEthernet ports belong to VLAN1. Different types of IPv6 addresses are configured for the VLAN 1 interface to verify the connectivity between two switches. The IPv6 prefix in the EUI-64 format is 2001::/64, the aggregatable global unicast address of Switch A is 3001::1/64, and the aggregatable global unicast address of Switch B is 3001::2/64.

II. Network diagram

Figure 1-7 Network diagram for IPv6 address configuration

III. Configuration procedure

1)         Configure Switch A.

# Enable the IPv6 packet forwarding function on Switch A.

<SwitchA> system-view

[SwitchA] ipv6

# Configure an automatically generated link-local address for the VLAN 1 interface.

[SwitchA] interface vlan-interface 1

[SwitchA-Vlan-interface1] ipv6 address auto link-local

# Configure an EUI-64 address for the VLAN 1 interface.

[SwitchA-Vlan-interface1] ipv6 address 2001::/64 eui-64

# Configure an aggregatable global unicast address for the VLAN 1 interface.

[SwitchA-Vlan-interface1] ipv6 address 3001::1/64

2)         Configure Switch B.

# Enable the IPv6 packet forwarding function.

<SwitchB> system-view

[SwitchB] ipv6

# Configure an automatically generated link-local address for the VLAN 1 interface.

[SwitchB] interface vlan-interface 1

[SwitchB-Vlan-interface1] ipv6 address auto link-local

# Configure an EUI-64 address for the VLAN 1 interface.

[SwitchB-Vlan-interface1] ipv6 address 2001::/64 eui-64

# Configure an aggregatable global unicast address for the VLAN 1 interface.

[SwitchB-Vlan-interface1] ipv6 address 3001::2/64

IV. Verification

# Display the brief IPv6 information of an interface on Switch A.

<SwitchA> display ipv6 interface vlan-interface 1

Vlan-interface1 current state :UP

Line protocol current state :UP

IPv6 is enabled, link-local address is FE80::7D6C:0:5C0C:1

  Global unicast address(es):

    2001::7D6C:0:5C0C:1, subnet is 2001::/64

    3001::1, subnet is 3001::/64

  Joined group address(es):

    FF02::1:FF0C:1

    FF02::1:FF00:1

    FF02::2

    FF02::1

  MTU is 1500 bytes

  ND DAD is enabled, number of DAD attempts: 1

  ND reachable time is 30000 milliseconds

ND retransmit interval is 1000 milliseconds

  Hosts use stateless autoconfig for addresses

# Display the brief IPv6 information of the interface on switch B.

<SwitchB> display ipv6 interface vlan-interface 1

Vlan-interface1 current state :UP

Line protocol current state :UP

IPv6 is enabled, link-local address is FE80::E525:0:F01D:1

  Global unicast address(es):

    2001::E525:0:F01D:1, subnet is 2001::/64

    3001::2, subnet is 3001::/64

  Joined group address(es):

    FF02::1:FF00:2

    FF02::1:FF1D:1

    FF02::2

    FF02::1

  MTU is 1500 bytes

  ND DAD is enabled, number of DAD attempts: 1

  ND reachable time is 30000 milliseconds

ND retransmit interval is 1000 milliseconds

  Hosts use stateless autoconfig for addresses

# On Switch A, ping the link-local address, EUI-64 address, and aggregatable global unicast address of Switch B. If the configurations are correct, the above three types of IPv6 addresses can be pinged.

 

 

<SwitchA> ping ipv6 FE80::E525:0:F01D:1 -i vlan-interface 1

  PING FE80::E525:0:F01D:1 : 56  data bytes, press CTRL_C to break

    Reply from FE80::E525:0:F01D:1

    bytes=56 Sequence=1 hop limit=255  time = 80 ms

    Reply from FE80::E525:0:F01D:1

    bytes=56 Sequence=2 hop limit=255  time = 60 ms

    Reply from FE80::E525:0:F01D:1

    bytes=56 Sequence=3 hop limit=255  time = 60 ms

    Reply from FE80::E525:0:F01D:1

    bytes=56 Sequence=4 hop limit=255  time = 70 ms

    Reply from FE80::E525:0:F01D:1

    bytes=56 Sequence=5 hop limit=255  time = 60 ms

 

  --- FE80::E525:0:F01D:1 ping statistics ---

    5 packet(s) transmitted

    5 packet(s) received

    0.00% packet loss

    round-trip min/avg/max = 60/66/80 ms

 

<SwitchA> ping ipv6 2001::E525:0:F01D:1

  PING 2001::E525:0:F01D:1 : 56  data bytes, press CTRL_C to break

    Reply from 2001::E525:0:F01D:1

    bytes=56 Sequence=1 hop limit=255  time = 40 ms

    Reply from 2001::E525:0:F01D:1

    bytes=56 Sequence=2 hop limit=255  time = 70 ms

    Reply from 2001::E525:0:F01D:1

    bytes=56 Sequence=3 hop limit=255  time = 60 ms

    Reply from 2001::E525:0:F01D:1

    bytes=56 Sequence=4 hop limit=255  time = 60 ms

    Reply from 2001::E525:0:F01D:1

    bytes=56 Sequence=5 hop limit=255  time = 60 ms

 

  --- 2001::E525:0:F01D:1 ping statistics ---

    5 packet(s) transmitted

    5 packet(s) received

    0.00% packet loss

    round-trip min/avg/max = 40/58/70 ms

 

<SwitchA> ping ipv6 3001::2

  PING 3001::2 : 56  data bytes, press CTRL_C to break

    Reply from 3001::2

    bytes=56 Sequence=1 hop limit=255  time = 50 ms

    Reply from 3001::2

    bytes=56 Sequence=2 hop limit=255  time = 60 ms

    Reply from 3001::2

    bytes=56 Sequence=3 hop limit=255  time = 60 ms

    Reply from 3001::2

    bytes=56 Sequence=4 hop limit=255  time = 70 ms

    Reply from 3001::2

    bytes=56 Sequence=5 hop limit=255  time = 60 ms

 

  --- 3001::2 ping statistics ---

    5 packet(s) transmitted

    5 packet(s) received

    0.00% packet loss

    round-trip min/avg/max = 50/60/70 ms

 

Chapter 2  IPv6 Application Configuration

2.1  Introduction to IPv6 Application

IPv6 has become widely used as it is developing with time. Most of IPv6 application are the same as those of IPv4, including:

l           Ping

l           Traceroute

l           FTP

l           TFTP

l           Telnet

2.2  Ping IPv6

Follow the following step to ping IPv6:

To do…	Use the command…	Remarks
Ping IPv6	ping ipv6 [ -a source-ipv6-address | -c count | -m interval | -s packet-size | -t timeout ]* remote-system [ -i interface-type interface-number ]	Required Available within any view

 

 

2.3  Traceroute IPv6

Traceroute IPv6 is used to record the route of IPv6 packets from source to destination, so as to check whether the link is available and determine the point of trouble.

Figure 2-1 Traceroute process

As Figure 2-1 shows, the traceroute process is as follows:

l           The source sends a IPv6 datagram with Hop Limit as 1 (the UDP port number of the carrier UDP packet is a port number that is not available to any application in the destination.

l           If the first device receiving the datagram reads the Hop Limit as 1, it will discard the packet and return a ICMPv6 timeout error message. Thus, the source can get the first device’s address in the route.

l           The source sends a datagram with Hop Limit as 2 and the second hop device returns a ICMPv6 timeout error message. And the source gets the second device’s address in the route.

l           This process continues until the datagram reaches the destination host. As there is no application using the UDP port, the destination returns a “port unreachable” ICMPv6 error message.

l           The source receives the “port unreachable” ICMPv6 error message and understands that the packet has reached the destination, thus determines the route of the packet from source to destination.

Follow the following step to traceroute IPv6:

To do…	Use the command…	Remarks
Traceroute IPv6	tracert ipv6 [ -f first-ttl | -m max-ttl | -p port | -q packet-number | -w timeout ]* remote-system	Required Available within any view

 

2.4  FTP Configuration

IPv6 supports file transfer protocol (FTP) applications. You can log into the switch (serving as an FTP client) by running the terminal emulation program on your PC or by using Telnet. Then, you can use the ftp command to connects the switch to a remote FTP server and access the files on the remote FTP server.

2.4.1  Configuration Prerequisites

The FTP server is started, with the related parameters, such as username, password, and user rights, configured. Refer to File System Management module for detailed procedures.

2.4.2  Logging in to the FTP Server

You can log in to the FTP server in the following two ways:

l           Enter FTP client view and log in to the FTP server by using the open ipv6 command.

l           Log in to the FTP server directly by using the ftp ipv6 command.

Table 2-1 Log in to the FTP server

To do…		Use the command…	Remarks
Log in to the FTP server directly and enter FTP client view		ftp ipv6 remote-system [ port-number ] [ -a source-ipv6-address ] [ -i interface-type interface-number ]	Either is required and you can choose only one login mode. Perform these operations in user view.
Log in to the FTP server in FTP client view	Enter FTP client view	ftp ipv6
	Log in to the FTP server	open ipv6 remote-system [ port-number ] [ -a source-ipv6-address ] [ -i interface-type interface-number ]

 

 

2.5  TFTP Configuration

IPv6 supports TFTP (Trivial File Transfer Protocol). As a client, the device can download files from or upload files to a TFTP server.

2.5.1  Configuration Preparation

Start the TFTP server and specify the route to download or upload files. Refer to TFTP server configuration specifications for specific instructions.

2.5.2  TFTP Configuration

I. Manage users’ access to TFTP servers

Follow these steps to configure the relation of ACL to TFTP application:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Configure the relation of ACL to TFTP application to enable or disable the access to a specific TFTP server	tftp-server ipv6 acl acl-number	Required ACL is not related to TFTP application by default.

 

II. Download files

Following the following steps to download files from TFTP servers

To do…	Use the command…	Remarks
Download files from TFTP server	tftp ipv6 remote-system [ -i interface-type interface-number ] get source-filename [ destination-filename ]	Required Available in user view

 

 

III. Upload files

Follow the following steps to upload files to TFTP servers:

To do…	Use the command…	Remarks
Upload files to TFTP servers	tftp ipv6 remote-system [-i interface-type interface-number ] put source-filename [ destination-filename ]	Required Available in user view

 

 

2.6  IPv6 Telnet

Telnet protocol belongs to application layer protocols of the TCP/IP protocol suite, and is used to provide remote login and virtual terminals. The device can be used either as a Telnet client or a Telnet server.

As the following figure shows, the Host is running Telnet client application of IPv6 to set up an IPv6 Telnet connection with Device A, which serves as the Telnet server. If Device A again connects to Device B through Telnet, the Device A is the Telnet client and Device B is the Telnet server.

Figure 2-2 Providing Telnet services

2.6.1  Configuration Prerequisites

Telnet has three kinds of authentications: None, Password and Scheme, with the default as Password. Refer to Login module for specific instructions.

2.6.2  Setting up IPv6 Telnet Connections

Follow the following steps to set up IPv6 Telnet connections:

To do…	Use the command…	Remarks
Perform the Telnet command at the Telnet client to login and manage other devices	telnet ipv6 remote-system [ -i interface-type interface-number ] [ port-number ]	Required Available in user view

 

 

2.6.3  Displaying and Maintaining IPv6 Telnet

Follow the following steps to display IPv6 Telnet:

To do…	Use the command…	Remarks
Display the use information of the user’s interface	display users [ all ]	Available in any view

 

2.7  Examples of Typical IPv6 Application Configurations

2.7.1  Network requirements

In Figure 2-3, SWA, SWB and SWC represent three switches. In the same LAN, there is a Telnet server and a TFTP server for providing Telnet service and TFTP service to the switch respectively.

2.7.2  Network diagram

Figure 2-3 IPv6 application network diagram

2.7.3  Configuration procedure

 

 

# Ping SWB’s IPv6 address from SWA.

<SWA> ping ipv6 3003::1

  PING 3003::1 : 56  data bytes, press CTRL_C to break

    Reply from 3003::1

    bytes=56 Sequence=1 hop limit=255  time = 2 ms

    Reply from 3003::1

    bytes=56 Sequence=2 hop limit=255  time = 2 ms

    Reply from 3003::1

    bytes=56 Sequence=3 hop limit=255  time = 2 ms

    Reply from 3003::1

    bytes=56 Sequence=4 hop limit=255  time = 2 ms

    Reply from 3003::1

    bytes=56 Sequence=5 hop limit=255  time = 2 ms

 

--- 3003::1 ping statistics ---

  5 packet(s) transmitted

  5 packet(s) received

  0.00% packet loss

  round-trip min/avg/max = 2/2/2 ms

# Trace the IPv6 route from SWA to SWC.

<SWA> tracert ipv6 3002::1

 traceroute to 3002::1  30 hops max,60 bytes packet

 1  3003::1 30 ms  0 ms  0 ms

 2  3002::1 10 ms 10 ms 0 ms

# SWC download a file from TFTP server 3001::3.

<SWC> tftp ipv6 3001::3 get filetoget flash:/filegothere

  Transfer file in binary mode.

  Now begin to download file from remote tftp server, please wait for a while...

  TFTP:    11369 bytes received in 1 seconds.

  File downloaded successfully.

# Connect to Telnet server 3001::2.

<SWA> telnet ipv6 3001::2

Trying 3001::2...

Press CTRL+K to abort

Connected to 3001::2 ...

Telnet Server>

# Set up a Telnet connection from SWA to SWC.

<SWA> telnet ipv6 3002::1

Trying 3002::1 ...

Press CTRL+K to abort

Connected to 3002::1 ...

*********************************************************************

* Copyright(c) 2004-2006 Hangzhou H3C Technologies Co., Ltd.  *

* Without the owner's prior written consent,                        *

* no decompiling or reverse-engineering shall be allowed.           *

*********************************************************************

 

<SWC>

2.8  Troubleshooting IPv6 Application

2.8.1  Unable to Ping a Remote Destination

I. Symptom

Unable to Ping a remote destination and return an error message.

II. Solution

l           Use the display ipv6 interface command to determine the interfaces of the source and the destination and the link-layer protocol between them are in the up state.

l           Use the display current-configuration command to check whether the IPv6 forward function is enabled. If not, enable it with the ipv6 command.

l           Use the ping ipv6 -t timeout remote-system [ -i interface-type interface-number ] command to increase the timeout time limit, so as to determine whether it is due to the timeout limit is too small.

2.8.2  Unable to Run Traceroute

I. Symptom

Unable to trace the route by performing Traceroute operations.

II. Solution

l           Determine whether you can Ping the destination host.

l           If yes, check whether the UDP port used by Traceroute has the required application in the destination host If yes again, specify a UDP port that is unreachable in the tracert ipv6 command.

2.8.3  Unable to Run FTP

I. Symptom

Unable to download and upload files by performing FTP operations.

II. Solution

l           Determine the FTP server application is running on the server. Check the configuration allows the server reachable.

l           Determine that the file system of the device is usable. You can check it by running the dir command under the user view.

l           Determine the route between the device and the FTP client is available.

2.8.4  Unable to Run TFTP

I. Symptom

Unable to download and upload files by performing TFTP operations.

II. Solution

l           Determine that the ACL configured for the TFTP server does not block the connection to the TFTP server.

l           Determine that the file system of the device is usable. You can check it by running the dir command under the user view.

l           Determine the route between the device and the TFTP server is available.

2.8.5  Unable to Run Telnet

I. Symptom

Unable to login to Telnet server by performing Telnet operations.

II. Solution

l           Determine the Telnet server application is running on the server. Check the configuration allows the server reachable.

l           Determine the route between the device and the Telnet client is available.