Discard ::/127

[hfakoor222]

My output from sh ipv6

::/0
no route
::/127
discard
2001:DB8:ACAD:1001::/64
attached to GigabitEthernet0/0
2001:DB8:ACAD:1001::2/128
receive for GigabitEthernet0/0
FE80::/10
receive for Null0
FF00::/8
multicast

what means ::/127 discard? everything up to ::/127 not defined 

in

2001:DB8:ACAD:1001::/64
attached to GigabitEthernet0/0
2001:DB8:ACAD:1001::2/128
receive for GigabitEthernet0/0

gets discarded?

[MHM Cisco World · Accepted solution]

The IP address ::/127 is called a loopback address. Packets sent to this address never reach the network but are looped through the network interface card only.

[Harold Ritter]

Hi @hfakoor222 ,

According to RFC4291, ::/128 is the unspecified IPv6 address and ::1/128 (equivalent to ipv4 0.0.0.0) is the loopback address (equivalent to IPv4 127.0.0.1). "::/127 discard" means that IOS will discard any packets destined to either addresses.

For more information about ::/128 or ::1/128 please refer to RFC4291.

https://datatracker.ietf.org/doc/html/rfc4291

Regards,