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

[mrzaz]

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

[databeestje]

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

[mrzaz]

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

[databeestje]

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.

[mrzaz]

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. :-)

[bardelot]

@mrzaz:

Any estimates when 4.3 will be included ?

4.3 does not yet exist. The current version is 4.2.4

[mrzaz]

OK