RE: interesting part 2

[Shane Hunt]

Atif,   A couple of things I do to try and isolate the problem...   See if you can do an extended ping to the DHCP server from the Ethernet segment your end stations are attached to (please don't take offense to this, this one bites me a lot.. I get so wound up in trying to find more elaborate causes to my problem that I sometimes overlook simple routing issues.)   The next thing I do, is put a sniffer on the segment with the DHCP server to see if indeed the packets are not reaching it.  (I also have wan sniffers that I use to troubleshoot this, If you have them I would recommend using them)  I will assume that you do not and show you how I troubleshoot this through IOS.   To debug this through IOS I do a "debug ip udp" on the router attached to the end stations (could produce a lot of data depending on your network!)   You should see something like   00:31:54: UDP: rcvd src=0.0.0.0(68), dst=255.255.255.255(67), length=308 ("The actual DHCP broadcast") 00:31:54: BOOTP: opcode 1 from host 0.0.0.0 on Ethernet0, 0 secs, 0 hops 00:31:54: UDP: forwarded broadcast 67 from 10.1.172.139("the router address") to 10.5.41.5("The DHCP server address") on Ethernet0   Next, set up an access-list that watches traffic destined to your DHCP server on your 2620, then you can do a "debug ip packet 1" (where 1 is the access-list you set up) you should see something like   00:08:18: IP: s=10.1.172.139 (Ethernet0), d=10.5.41.5 (Ethernet1), g=10.5.41.5, len 328, forward ("This is the forwarded packet")   (The output from these debugs might look a little different as I have these routers sitting on the same ethernet segment and not across a WAN.... But it should illustrate the point)   You should be able to do this debug throughout your network and watch the packets flow from end to end.   I hope this helps you out!   Shane     From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Atif Awan Sent: Friday, July 07, 2000 2:11 PM To: [EMAIL PROTECTED] Subject: interesting part 2 well the scenario is the same .. 3 routers connected in a hub and spoke topology with the 2620 ( IOS 12.1(1)) as the hub. This time the DHCP is not working across the WAN. it used to work fine before the 2620 came in .. are there any IOS 12.1(1) bugs or something like that which will prevent it from functioning properly.   i am also looking it up on the cisco web site but if anyone knows the solution first do post it :)   Regards Atif