Two great IPv6 Goodies

Two great IPv6 Goodies

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If you are not familiar with IPv6 it works slightly differently then IPv4 when it comes to troubleshooting.  One of the issues I ran into is that I depend on ARP often when dealing with Layer 2/3 issues.  ARP as we know it in IPv4 doesn’t exist in IPv6.  Instead it uses a part of ICMPv6 which is incorporated into the protocol called Neighbor Discovery (ND).  The command to see directly connected IPv6 neighbors is:

show ipv6 neighbor ethernet 0/0

R1#show ipv6 neigh eth 0/0
IPv6 Address Age Link-layer Addr State Interface
FC00:192:1:12::2 22 aabb.cc00.0200 STALE Et0/0
FE80::A8BB:CCFF:FE00:200 9 aabb.cc00.0200 STALE Et0/0

R1#

 

Another command that is useful in IPv4 that I was not aware of and also works in IPv6 is the show ipv6 cef exact-route.  In the example below FC00:1:1:1::1 is the  loopback 0 interface.   FC00:2:2:2::2 is the Loopback 0 interface of the connected neighbor R2 connected on Interface Ethernet 0/0.

R1#show ipv6 cef exact-route fc00:1:1:1::1 fc00:2:2:2::2
FC00:1:1:1::1 -> FC00:2:2:2::2 =>IPV6 adj out of Ethernet0/0, addr FE80::A8BB:CCFF:FE00:200
R1#show ipv6 neigh eth 0/0
IPv6 Address Age Link-layer Addr State Interface
FC00:192:1:12::2 22 aabb.cc00.0200 STALE Et0/0
FE80::A8BB:CCFF:FE00:200 9 aabb.cc00.0200 STALE Et0/0

 

 

 

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