Problem with DHCPv6 stops processing "Solicit XID" messages from clients.



  • I have seen intermittent problems with DHCPv6 server that from time to time stops processing "Solicit XID" messages from clients.
    If I do a OFF/ON switching of the DHCPv6 server it starts working again.

    I have tested to have DHCP6 ENABLED and then go from RA Mode Unmanaged to Managed but then I only get

    112 3.803110 fe80::39cf:c6b0:4657:c4ed ff02::1:2 DHCPv6 147 Solicit XID: 0xc6266e CID: 00010001153faa28f46d04063ba8
    121 4.802511 fe80::39cf:c6b0:4657:c4ed ff02::1:2 DHCPv6 147 Solicit XID: 0xc6266e CID: 00010001153faa28f46d04063ba8
    361 6.802591 fe80::39cf:c6b0:4657:c4ed ff02::1:2 DHCPv6 147 Solicit XID: 0xc6266e CID: 00010001153faa28f46d04063ba8
    437 10.802745 fe80::39cf:c6b0:4657:c4ed ff02::1:2 DHCPv6 147 Solicit XID: 0xc6266e CID: 00010001153faa28f46d04063ba8
    540 18.803159 fe80::39cf:c6b0:4657:c4ed ff02::1:2 DHCPv6 147 Solicit XID: 0xc6266e CID: 00010001153faa28f46d04063ba8
    734 34.803762 fe80::39cf:c6b0:4657:c4ed ff02::1:2 DHCPv6 147 Solicit XID: 0xc6266e CID: 00010001153faa28f46d04063ba8

    If I then put DHCP Enabled to unchecked and press SAVE and then back to checked and press save, I get the following:

    1264 66.804653 fe80::39cf:c6b0:4657:c4ed ff02::1:2 DHCPv6 193 Request XID: 0xc6266e CID: 00010001153faa28f46d04063ba8 IAA: 2001:470:28:dd5::9266
    1161 60.223978 fe80::66e6:82ff:fed0:7695 ff02::1:2 DHCPv6 160 Renew XID: 0x646299 CID: 00010001176a28b564e682d07695 IAA: 2001:470:28:dd5::bd39
    1263 66.804490 fe80::82ee:73ff:fe18:9ab7 fe80::39cf:c6b0:4657:c4ed DHCPv6 166 Advertise XID: 0xc6266e IAA: 2001:470:28:dd5::9266 CID: 00010001153faa28f46d04063ba8
    1265 66.804983 fe80::82ee:73ff:fe18:9ab7 fe80::39cf:c6b0:4657:c4ed DHCPv6 166 Reply XID: 0xc6266e IAA: 2001:470:28:dd5::9266 CID: 00010001153faa28f46d04063ba8
    (This client had previously been assigned via DHCP)

    I then tried to release old assigned IP and renew again.
    208 26.592067 fe80::39cf:c6b0:4657:c4ed ff02::1:2 DHCPv6 147 Solicit XID: 0x5d953c CID: 00010001153faa28f46d04063ba8
    209 26.592375 fe80::82ee:73ff:fe18:9ab7 fe80::39cf:c6b0:4657:c4ed DHCPv6 166 Advertise XID: 0x5d953c IAA: 2001:470:28:dd5::9266 CID: 00010001153faa28f46d04063ba8
    244 27.591698 fe80::39cf:c6b0:4657:c4ed ff02::1:2 DHCPv6 193 Request XID: 0x5d953c CID: 00010001153faa28f46d04063ba8 IAA: 2001:470:28:dd5::9266
    245 27.592049 fe80::82ee:73ff:fe18:9ab7 fe80::39cf:c6b0:4657:c4ed DHCPv6 166 Reply XID: 0x5d953c IAA: 2001:470:28:dd5::9266 CID: 00010001153faa28f46d04063ba8
    (normal DHCP request/assignment)

    Then again tried different combinations of trying to force to stop working but could not do it.

    I also tried to compare 2 Solicit XID before and after I "restarted" the DHCPv6 but it was identical except "elapsed time" entry.
    Also did the same with 2 RA and they where identical.

    Can't put my finger on why sometimes the DHCPv6 server stops processing requests.

    I have seen that similar issues has been discussed in forum but no real answer. 
    If this has already been discussed to the end, send me a link where to read about it.

    I did tests on build Sat Jun 16 14:16:56 EDT 2012 and also earlier builds with same results.

    Best regards
    Dan Lundqvist
    Stockholm, Sweden



  • There are quite a few cases where the IPv6 support in ISC dhcpd is lacking. Out of leases is a good example.

    I suspect a lot of this will be tied up in 4.3



  • That so, but in this case it was a "Windows 7 Ultimate Edition 64bit" client and not a mobile. :-)

    And as you could see, the Solicit message is sent but not acted on by the router.

    //Danne



  • To clarify, I meant the ISC dhcpd server in pfSense, and I suspect that version 4.3 will fix quite a few of the dhcp6 server issues. We are using 4.2.3 now.



  • Ahh…  Thought you meant "ICS" as in IceCreamSandwitch" but see now that you wrote ISC... My fault.  bummer :-)

    Any estimates when 4.3 will be included ?
    Just curious, it is not critical for me as I am running in Unmanaged mode right now.
    It is more of a "i am exploring all aspects of IPv6" now when I finally have started looking into v6. :-)



  • @mrzaz:

    Any estimates when 4.3 will be included ?

    4.3 does not yet exist. The current version is 4.2.4



  • OK


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