[Gllug] Resolving host names from a dhcp server

[Ian Northeast]

N.Pauli wrote:

> You're perfectly correct. The 'something here that I am missing' was a 
> confusion of dhcp with dns. Linuxbox is not a server so dhcp is ok for it. 
> As suggested I did "ipconfig /all" on a windows client and found that it's 
> using 10.0.0.3 for its dhcp and dns server. linuxbox's /etc/resolv.conf 
> lists 10.0.0.3 as its first nameserver with 127.0.0.1 as the second - and 
> yet no joy. 

You'll also have to ensure that the DHCP server updates the DNS server 
when it assigns leases. I've done this with a Windows DHCP server and 
bind on Linux, but never with the Windows DNS server which it sounds 
like you've got. I wouldn't expect it to be difficult. Basically you 
have to configure the DHCP server to send the updates and the DNS server 
to accept them. I recall that it's a fairly obvious option in the DHCP 
server and it probably is in the DNS server too. But I only ever set up 
a Windows DNS server once, years ago, and that was only to prove that a 
hosting provider who wanted to charge us for 2 man days for the job was 
taking the piss.

It's also possible to have DHCP clients update the DNS server 
themselves, and Windows clients love to try this. I think it's a stupid 
idea. You can, presumably, trust your DHCP server not to send duff 
updates but how can you trust the clients? Our public facing nameservers 
which host our external domains get constant hits from PCs on our LAN 
trying to register themselves into one - when we do not use the public 
domains on the LAN, we have private ones. It is an axiom IMO that client 
PCs will be misconfigured.

As Stephen Harker mentioned, the Windows machines are probably using 
NetBIOS name resolution to resolve names for TCP/IP connections. Windows 
does this. I do not believe that Linux can. AFAIK there is no RFC 
sanctioning Windows' behaviour (is there any RFC which sanctions any 
aspect of Windows' behaviour?) Linux generally goes by the RFCs.

Regards, Ian

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