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• For a Loopback interface, enter the keyword loopback
then a number from 0 to 16383.
• For a port channel interface, enter the keywords port-
channel
then a number.
• For a VLAN interface, enter the keyword vlan then a
number from 1 to 4094.
Defaults Not configured.
Command
Modes
CONFIGURATION
Command
History
Version Description
9.7(0.0) Introduced on the S6000-ON.
9.3(0.0) Introduced on the S4810, S4820T, S6000, and Z9000
platforms.
Usage
Information
You can enable the mechanism to configure the source or the originating interface
from which the packet (the device that generates the ICMP error messages) is
received by the switch to send the loopback address instead of its source IP
address to be used in the ICMP unreachable messages and in the
traceroute
command output. The loopback address must be unique in a particular domain.
In network environments that contain a large number of devices, ranging up to
thousands of systems, and with each device configured for equal-cost multipath
(ECMP) links, you cannot effectively and optimally use the traceroute and ping
applications to examine the network reachablity and identify any broken links for
diagnostic purposes. In such cases, if the reply that is obtained from each hop on
the network path contains the IP address of the adjacent, neighboring interface
from which the packet is received, it is difficult to employ the ping and traceroute
utilites. You can enable the ICMP unreachable messages to contain the loopback
address of the source device instead of the previous hop's IP address to be able to
easily and quickly identify the device and devices along the path because the DNS
server maps the loopback IP address to the hostname and does not translate the IP
address of every interface of the switch to the hostname.
Example
Dell(conf)#ip icmp source-interface tengigabitethernet 1/1
Dell(conf)#
ipv6 icmp source-interface
Enable the ICMP error and unreachable messages to be sent with the source interface IP address, such as
the loopback address, instead of the hops of the preceding devices along the network path to be used for
easy debugging and diagnosis of network disconnections and reachability problems with IPv6 packets.
Syntax
ipv6 icmp source-interface interface
IPv4 Routing
769