The environment at work is a mix of Windows and Unix.  The standard build for the laptops is Windows XP, with a few Macs.  Oh and the the odd Linux install   Of course with a network of a certain size then DHCP becomes the only option for allocating addresses to devices other than servers, printers and the like (which must be on a static address).

But that doesn’t mean that it’s all well and jolly, especially when you have windows admin who run the central services including DHCP.

In my case I couldn’t work out why only certain hostnames could be resolved after I picked up an address via DHCP on my linux machine.  Some addresses were getting a SERVFAIL repsponse from the internal DNS servers.  Did I have a proper IP address – check, dns servers – check, dns search domain – check.  All in order.  Time to compare with a windows machine which could resolve all hostnames.

What’s that I spy?  Three more dns search domains! Eh?  Where did they come from?  I added these ‘extra’ search domains into /etc/resolve.conf and all those hostnames that didn’t resolve before suddenly popped into life.  Next step to check with the admins and see if DHCP server was behaving correctly.

No reported problem there.  Next question – how is the dhcp server configured for dns search domains.  “Only the one is given through the DHCP request, the rest are given through group policy.”  That explains a lot.  Linux machines don’t pick up dns search domains given out via a windows group policy.

Just as I left this evening I had a quick chat with one of the more senior and knowledgeable staff who is  a Mac user, and no surprise there but he has the same problem but didn’t realise it.  As a result of this this quick conversation it sounds like there may be a change to the DHCP server in the near future.