no DHCPACK

Simon Hobson dhcp1 at thehobsons.co.uk
Thu Nov 15 22:13:48 UTC 2007


Beavis wrote:

>  I have the following setup below:
>
>dhcp-server <-->e0[fwall]e1<--[s3750]<-- dhcp-clients
>
>whenever i tried to request for a lease from my clients i only get a
>DHCPDISCOVER and DHCPOFFER but no DHCPACK traffic sent by the client.
>
>Nov 15 15:01:04 proxy01 dhcpd: DHCPDISCOVER from 00:08:02:01:b7:36
>(c8m3sibaa2njkd1) via 10.0.5.1
>Nov 15 15:01:05 proxy01 dhcpd: DHCPOFFER on 10.0.5.50 to
>00:08:02:01:b7:36 (c8m3sibaa2njkd1) via 10.0.5.1
>Nov 15 15:01:08 proxy01 dhcpd: DHCPDISCOVER from 00:08:02:01:b7:36
>(c8m3sibaa2njkd1) via 10.0.5.1
>Nov 15 15:01:08 proxy01 dhcpd: DHCPOFFER on 10.0.5.50 to
>00:08:02:01:b7:36 (c8m3sibaa2njkd1) via 10.0.5.1
>Nov 15 15:01:16 proxy01 dhcpd: DHCPDISCOVER from 00:08:02:01:b7:36
>(c8m3sibaa2njkd1) via 10.0.5.1
>Nov 15 15:01:16 proxy01 dhcpd: DHCPOFFER on 10.0.5.50 to
>00:08:02:01:b7:36 (c8m3sibaa2njkd1) via 10.0.5.1
>Nov 15 15:01:33 proxy01 dhcpd: DHCPDISCOVER from 00:08:02:01:b7:36
>(c8m3sibaa2njkd1) via 10.0.5.1
>Nov 15 15:01:33 proxy01 dhcpd: DHCPOFFER on 10.0.5.50 to
>00:08:02:01:b7:36 (c8m3sibaa2njkd1) via 10.0.5.1
>
>is there anything else i might be missing on this? my clients are windowsxp's

In this sort of situation you need to work methodically through the 
network to "follow the packets". There is insufficient information to 
tell if :

1) the offer fails to reach the client
2) The client ignores it (does it have everything the client needs ?)
3) The request from the client fails to reach the server
4) Something else - such as a router, firewall, or switch being 
'helpful' and mangling packets in some way that breaks things.

I would be inclined to sniff packets on the client part of the 
network first - see if you can see the initial offer and then a 
request from the client. Settling this should allow you to narrow 
down the problem a bit.


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