Newbie IPv6 question

Probably a very simple one. Two of my machines (both OVZ if it matters) have this address listed alongside the public IPv6 address:

inet6 ::2/128 scope global

I know ::1 is loopback but what is ::2 for and do I need it?


  • is like gateway and your first ip

    Thanked by (3)vpsgeek WSS notty
  • Thanks, do you mean ::2 is a special address used just for the gateway? Is this an OpenVZ thing?

    I read in various places that ::/96 is reserved for IPv4-compatible addresses (deprecated) so at first I thought it was something like that.

  • WSSWSS Retired

    ::2 is your first usable IP. CIDR networking is still a thing in IPv6.

    :: just means <all unfilled up to your final not-an-octet. It's like shorthand for in ipv4 being "127::1."

    Thanked by (2)notty Ganonk

    My pronouns are asshole/asshole/asshole. I will give you the same courtesy.

  • Thanks. I think I do understand the notation. But I'm still confused, as ::2 surely isn't a public IP.
    And yet it appears with "global" scope alongside my public IPs...

    [email protected]:~# ip -6 a
    1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 state UNKNOWN qlen 1000
        inet6 ::1/128 scope host  <-- this is loopback
           valid_lft forever preferred_lft forever
        inet6 abcd:ab:c:d::567b/64 scope global <-- these are my public IPs
           valid_lft forever preferred_lft forever
        inet6 ::2/128 scope global  <-- but what's this address??
           valid_lft forever preferred_lft forever
  • I think thats point to point link to upstream gateway?

    Thanked by (1)notty
  • I was good at math until they mixed the alphabet into it.

  • The IPv6 address ::2/128 used on Openvz 7 is invalid. Using it is completely broken. Bird also fills the log with:

    KIF: Invalid interface address ::2 for venet0
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