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haariseshu 08-07-2009 01:49 AM

Problem on acquiring IP addr. on client from dhcp server through dhcp relay server
 
Hi Guys,

In our org.there are two different network. One is 192.168.1.x (where DHCP server exists) and 151.2.1.x (where DHCP relay server exists).

DHCP relay server got connected to both networks.

Now if a client from 151 network is requesting a IP addr. dhcp relay server receives the requests(no logs for that) and from dhcp relay server dhcp server is receiving the request and offering a IP on 151 series.

But client is unable to obtain the IP eventhough dhcp server is offering.

Here is my dhcp server log:

Quote:

Aug 7 12:07:14 SOL-01-03-MKTG dhcpd: DHCPDISCOVER from 00:15:5d:34:07:1a (test-02) via 151.2.1.1
Aug 7 12:07:14 SOL-01-03-MKTG dhcpd: DHCPOFFER on 151.2.1.200 to 00:15:5d:34:07:1a (test-02) via 151.2.1.1
----
--
repeating the same msg as above...

My guess is dhcp server is receiving a request from a dhcprelay server thru 151 series IP which its not able to communicate. So that when its trying to reply to the request on same IP it receives (151.2.1.1) its unable to connect.... This is only my guess...

Is there any way to overcome this problem...
Please help me...
Thanks a lot...

vikas027 08-07-2009 02:40 AM

I recommend you to post the output of logs of client too. It is /var/log/messages

You can dhclient -r

and then dhclient and post output of
Code:

tail -20 /var/log/messages | grep DHCP

haariseshu 08-07-2009 03:25 AM

Hi..

Thank you for your response...

You are asking for the dhcp client logs or dhcp relay server log??? Actually dhcp client that trying to acquire IP from dhcp server is basically a windows machine...

haariseshu 08-08-2009 08:14 AM

Guys....

Any idea!!!....

vikas027 08-08-2009 01:00 PM

Quote:

Originally Posted by haariseshu (Post 3634502)
Hi..

Thank you for your response...

You are asking for the dhcp client logs or dhcp relay server log??? Actually dhcp client that trying to acquire IP from dhcp server is basically a windows machine...

I was asking about DHCP client logs. Well if it is a window machine, I am useless. No idea about Windows. Sorry.

settntrenz 08-10-2009 01:20 AM

Quote:

Originally Posted by haariseshu (Post 3634449)
My guess is dhcp server is receiving a request from a dhcprelay server thru 151 series IP which its not able to communicate. So that when its trying to reply to the request on same IP it receives (151.2.1.1) its unable to connect.... This is only my guess...

It appears that the dhcp server is in fact getting the request (based on the existence of a log entry). That should mean that the relay server can in fact reach the dhcp server. The question is, does the dhcp server know how to reach the relay server?

Can you run a tcpdump on the dhcprelay server to determine if it is getting a reply from the dhcp server? If not, you need to look at the routing in the network. If so, you need to look at the dhcrelay config.

Sorry I don't have a definitive answer for you. Hopefully this will at least help rule some items out.


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