HP MSR2000/3000/4000 Router Series Layer 3 - IP Services Command Reference

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undo ip ttl-expires enable
Default
Sending ICMP time-exceeded packets is disabled.
Views
System view
Predefined user roles
network-admin
Usage guidelines
A device sends ICMP time-exceeded packets by following these rules:
• If a received packet is not destined for the device and the TTL field of the packet is 1, the device
sends an ICMP "TTL expired in transit" packet to the source.
• When the device receives the first fragment of an IP datagram destined for the device itself, it starts
a timer. If the timer expires before all the fragments of the datagram are received, the device sends
an ICMP "fragment reassembly timeout" packet to the source.
A device disabled from sending ICMP time-exceeded packets does not send ICMP "TTL expired" packets
but can still send ICMP "fragment reassembly timeout" packets.
Examples
# Enable sending ICMP time-exceeded packets.
<Sysname> system-view
[Sysname] ip ttl-expires enable
ip unreachables enable
Use ip unreachables enable to enable sending ICMP destination unreachable packets.
Use undo ip unreachables enable to disable sending ICMP destination unreachable packets.
Syntax
ip unreachables enable
undo ip unreachables enable
Default
Sending ICMP destination unreachable packets is disabled.
Views
System view
Predefined user roles
network-admin
Usage guidelines
A device sends ICMP destination unreachable packets by following these rules:
• If a packet does not match any specific route and there is no default route in the routing table, the
device sends a Network Unreachable ICMP error packet to the source.
• If a packet is destined for the device but the transport layer protocol of the packet is not supported
by the device, the device sends a Protocol Unreachable ICMP error packet to the source.