Some DHCis not created

Chris Buxton chris.p.buxton at
Thu Dec 9 17:54:10 UTC 2010

On Dec 9, 2010, at 7:11 AM, Nicolas Ecarnot wrote:
> Hi,
> Our DHCP servers set up in DDNS mode for ~1000 windows XP and ~300 other hosts are updating Windows 2003 servers DNS and it's working well.
> The DHCID are created, and when the DHCID doesn't exist and the A record does, I get the usual error message in the logs (not mine...)
> Deleting the A record, forcing a release/renew leads to a correct creation of the A record, the DHCID TXT record and the reverse.
> That's nice!
> But, for 5 ou 10 hosts, I see that the A record and the reverse get created but not the DHCID.
> That leads to the situation of the next DHCPREQUEST, where the DHCP server checks the presence of the DHCid, does not find it and complains.
> I the logs, I don't see a single word about the non-creation of the DHCID, and no one seem to had a similar issue on this mailing list...

Do you see a log message indicating that the A record was successfully created? If so, I suggest a packet sniffer to see what's being sent (and by what hosts). Perhaps you've found a bug in MS DNS -- something like, if two updates arrive for the same A record simultaneously (or close enough that DNS can't tell the difference), the first is incorporated into the zone and the second is not, but both are acknowledged without error message. Just speculating here...

Chris Buxton
BlueCat Networks

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