Clients not recieving IP's via DHCP

[Glenn Satchell]

>Date: Fri, 09 Feb 2007 21:18:22 +1300
>From: Tim Philips <timp at rndgroup.co.nz>
>To: dhcp-users at isc.org
>Subject: Re: Clients not recieving IP's via DHCP
>
>Glenn Satchell wrote:
>
>Hi Glenn (once again),
>
>Thanks Andy for your advice on increasing the capture size.  Below is a
>tcpdump of the output:
>
>21:10:56.334328 IP (tos 0x0, ttl  64, id 19400, offset 0, flags [none],
>proto 17, length: 328) 0.0.0.0.bootpc > 255.255.255.255.bootps:
>BOOTP/DHCP, Request from 00:0d:3a:4e:f4:da, length: 300, xid:0x889c873,
>flags: [none]
>          Client Ethernet Address: 00:0d:3a:4e:f4:da
>          Vendor-rfc1048:
>            DHCP:DISCOVER
>            CID:[ether]00:0d:3a:4e:f4:da
>            VC:"XBOX 1.0"
>            PR:SM+DG+NS
>            RQ:192.168.0.4
>21:10:56.441805 IP (tos 0x10, ttl  16, id 0, offset 0, flags [none],
>proto 17, length: 328) 127.0.0.1.bootps > 192.168.2.252.bootpc:
>BOOTP/DHCP, Reply, length: 300, xid:0x889c873, flags: [none]
>          Your IP: 192.168.2.252
>          Server IP: 192.168.2.1
>          Client Ethernet Address: 00:0d:3a:4e:f4:da
>          Vendor-rfc1048:
>            DHCP:OFFER
>            SID:127.0.0.1
>            LT:7200
>            SM:255.255.255.0
>            DG:192.168.2.1
>            NS:192.168.2.1
>
>
>From what I can tell the requirements are Subnet Mask, Default Gateway
>and Name Server which are all being relied to from the DHCP server.

Yes, that looks correct.

>Am I reading too much into this when it says "Your IP: 192.168.2.252"
>and "192.168.2.252.bootpc" when that isn't _yet_ the clients IP but
>would be if the client accepted the DHCP lease?

Yeah, you're reading too much into it. That's just the way tcpdump
decodes the field names. The field is for the address offered to the
client or requested by the client.

Interestingly, in the first packet which is the request from the client
it is asking for 192.168.0.4. The response should be a DHCPNAK to tell
the client it can't have this address. Seems like the server is not
doing this (at least nothing in the above seems to indicate that), so
the client keeps asking for it.

Your config looks ok, so I can only assume that it might be a bug in th
every old version of dhcpd you're running. Can you upgrade from 3.01 to
3.0.5? There are links to find RPMs on the ISC DHCPD web site.

Anotheridea would be to trace the traffic while the client is
requesting an address from the Windows dhcp server and compare the
packet contents. That might give a clue as to what the client wants.

regards,
-glenn