Wireshark is good and free.
As is the NetMon 3.0 from MS. Sniff a good DHCP lease conversation, and then a failed one and compare the two. -sc From: John Hornbuckle [mailto:[email protected]] Sent: Wednesday, February 17, 2010 9:47 AM To: NT System Admin Issues Subject: Troubleshooting DHCP Yesterday I started having some DHCP weirdness that has grown today. I'm kind of stumped and need some guidance. DHCP server is Windows Server 2008. It's also a DC and DNS server. It shows no errors relating to DHCP in Event Viewer, and there are plenty of addresses left in the scope. It can be pinged from client machines at >1 ms and no timeouts, and it can ping client machines with the same results. DNS is working fine. DC functions are working fine. DHCP, unfortunately, appears spotty. A number of clients (although apparently not all, from what I can tell) can't get leases. If you run ipconfig /renew from a command prompt, they report that they can't contact the DHCP server. If you manually assign an IP address, all works fine. So network connectivity seems okay-this seems to be strictly a DHCP issue. I'm guessing that I'm going to need a packet sniffer to further troubleshoot. I have to confess, though, that I've never in my life used one. I've just never needed to. So, can anyone recommend a free, simple packet sniffer I can run from a client machine to watch the DHCP traffic? And what, exactly, should I be looking for? John Hornbuckle MIS Department Taylor County School District www.taylor.k12.fl.us NOTICE: Florida has a broad public records law. Most written communications to or from this entity are public records that will be disclosed to the public and the media upon request. E-mail communications may be subject to public disclosure. ~ Finally, powerful endpoint security that ISN'T a resource hog! ~ ~ <http://www.sunbeltsoftware.com/Business/VIPRE-Enterprise/> ~
