The ip icmp ttl-exceeded source-address ingress-interface command forcibly configures the IP address of the inbound interface for forwarding packets as the source address of an ICMP Time Exceeded message.
The undo ip icmp ttl-exceeded source-address ingress-interface command restores the default configuration.
By default, the IP address of the inbound interface for forwarding packets is not forcibly configured as the source address of an ICMP Time Exceeded message.
Usage Scenario
Tracert is used to test the path through which a packet passes from a host to the destination. After receiving the packet, an intermediate device sends an ICMP Time Exceeded message to the host. The host then identifies the device according to the source IP address of the ICMP Time Exceeded message. To easily observe the inbound interface of a device along the path, you can configure the IP address of the inbound interface for forwarding packets as the source address of an ICMP Time Exceeded message.
Precautions
If both the ip icmp ttl-exceeded source-address ingress-interface and ip icmp ttl-exceeded source-address commands are configured, the ip icmp ttl-exceeded source-address command takes precedence over the ip icmp ttl-exceeded source-address ingress-interface command.
After the ip icmp ttl-exceeded source-address ingress-interface command is run, if a packet enters a device through a BAS interface, the device does not select an IP address from the address pool on the BAS interface.