MS Server 2003 DHCP Oddity/Bug

Hi all,

Thought i`d lay down my first post as a shout out to anyone who`s experienced/experiencing this particular issue and may know the cause/solution to it. We`ve been running a couple of DC`s with 2003 Server now for quite a while with no issues. We have our DHCP range split off into 2 smaller scopes that run off each of the DC`s. This worked fine until recently when i noticed that particular DHCP clients couldn`t contact the second of our 2 DC`s (ie - unable to ping etc...) even tho it was online and clients with static assigned IP`s could. After a bit of monkeying about on the 2nd DC i noticed something peculiar, a lot of the DHCP clients that had their leases on the 2nd DC had static ARP entries in the ARP table on the server when they should blatently be dynamic entries. I found it wierd that this wasn`t the case for all the clients that had been assigned leases and only a few random PC`s. I eventually bounced the DHCP Server service and manually raked out the static entries, upon doing so the proper dynamic ARP entries popped up in the table and the clients were once again able to communicate with the server and vice versa. I cannot fathom why this is happening as there isn`t any error logs against this and it doesn`t happen on the 1st DC. The 2nd DC is running a PXE and TFTP server (3Com boot services) if this has any bearing on the issue although it has worked in conjunction with DHCP fine for ages so i can`t see why this is an issue now,

If anyone can think of what the possible cause for this is then i would be grateful as i can`t see why this is happening, or even if someone has seen this before on any of theor systems just so i know i`m not alone with this one in a manner of speaking

Ta.

 

this is digging deep into the archives of random stuff i cannot prove, but isnt there something about using TFTP/bootP and static ARP entries. I am vaguely recalling something about if the transfer takes more than the arp cache timeout (10 minutes?), it will fail unless they are static entries.

Wonder if someone had added them to work around a problem a while back and everyone forgot about it.

 

Hmm interesting... i`ve had a look around on the net for information about that but can`t seem to find any pertaining to windows server 2003. I also wanted to check what the default arp cache timeout is, apparently for NT4 and 2000 it was 2 mins.... i can only assume it is that for server 2003 but i can`t be sure. In case this is causing an issue i`ve set the ARP cache timeout on the 2nd DC`s DHCP server`s options to be 10 mins, just to see if this has any bearing on the issue although i find it wierd that all has been fine for 2 months and only now this has occurred twice.

If you get anymore info on this give me a shout yeh, thanks for the heads up anyways Joe.