R21xx-HP FlexFabric 11900 Layer 3 IP Services Command Reference

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Default
Sending ICMPv6 redirect messages is disabled.
Views
System view
Predefined user roles
network-admin
Usage guidelines
The default gateway sends an ICMPv6 redirect message to the source of an IPv6 packet to inform of a
better first hop.
Sending ICMPv6 redirect messages enables hosts that hold few routes to establish routing tables and find
the best route. Because this function adds host route into the routing tables, host performance degrades
when there are too many host routes. As a result, sending ICMPv6 redirect messages is disabled by
default.
Examples
# Enable sending ICMPv6 redirect messages.
<Sysname> system-view
[Sysname] ipv6 redirects enable
ipv6 unreachables enable
Use ipv6 unreachables enable to enable sending ICMPv6 destination unreachable packets.
Use undo ipv6 unreachables to disable sending ICMPv6 destination unreachable packets.
Syntax
ipv6 unreachables enable
undo ipv6 unreachables enable
Default
Sending ICMPv6 destination unreachable packets is disabled.
Views
System view
Predefined user roles
network-admin
Usage guidelines
If the device fails to forward a received IPv6 packet because of a destination unreachable error, it drops
the packet and sends a corresponding ICMPv6 Destination Unreachable error message to the source.
If the device is generating ICMPv6 destination unreachable messages abnormally, disable sending
ICMPv6 destination unreachable packets to prevent attack risks.