Computers are receiving multiple IP addresses with IPv6 and SixXS tunnel



  • So I'm having a weird issue.  Not sure it's a problem exactly, but it worries me a bit.

    I set up a working SixXS IPv6 tunnel using the latest guide and everything seems to be working okay.  When I test my IPv6 connectivity everything comes out like it should, except for my IP address.

    While I can access IPv6 websites just fine, the public IP address that various "what's my IPv6 IP" show me is different than anything I set up in the DHCPv6 server.  For example, the highest IPv6 address the DHCP server should be handing out is 2001:1938:XXXX:XXXX:0:0:0:FFFF, but according to test-ipv6 my IP address is 2001:1938:XXXX:XXXX:c006:329b:1a64:73cf.

    Alright, that's confusing enough, but then when I go to check ipconfig I get some rather curious entries:

    IPv6 Address. . . . . . . . . . . : 2001:1938:XXXX:XXXX::ff9e(Preferred)
      Lease Obtained. . . . . . . . . . : Saturday, April 12, 2014 7:25:14 PM
      Lease Expires . . . . . . . . . . : Saturday, April 12, 2014 9:25:14 PM
      IPv6 Address. . . . . . . . . . . : 2001:1938:XXXX:XXXX:8987:7c8a:2e3e:8e12(Preferred)
      Temporary IPv6 Address. . . . . . : 2001:1938:XXXX:XXXX:c006:329b:1a64:73cf(Preferred)

    I can't imagine having multiple IPs is a good thing.  Of course, maybe I'm wrong.  Regardless, I would like to eliminate this weirdness if I can.  I considered disabling the DHCP server, but without it I get no IPv6 DNS entries for my computers.

    Feel free to tell me I'm being silly and shouldn't worry if that is in fact the case.  Just seems odd is all.



  • You are indeed wrong; this is perfectly normal for IPv6. Typically an IPv6-enabled host will have a SLAAC address (generated from the NIC's MAC), a temporary address (IPv6 privacy extensions), and possibly a DHCPv6-assigned address on each v6-enabled interface, plus link-local addresses. For privacy reasons, the temporary address is what will generally be used for outbound connections (which is what those websites will see); however, you should still be reachable at the other addresses for inbound connections.


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