DNS or DHCP Problem

I have a domain that is entirely Windows 2000. There are 3 DC's but one of them is also the DNS and DHCP server.

When I migrated all the workstations to the new domain (two years ago) I found a problem that happened only occasionally. A user would log on and the process would take 3-5 minutes. I never managed to pin down the reason for this as it didn't stick to any particular type of machine or user but found a solution by specifying the IP address of the DNS server in the network properties of each workstation,over-riding the DHCP settings on each machine.

All users are on roaming profiles, are power users of their normal workstations, and the DNS and DHCP settings on the server will be pretty much default.

Now we have a problem that some users are not connecting to frequently used websites fast enough. This doesnt happen with every user or with every website, but it has been affecting our CEO, and he shouts alot. IE just seems to hang for 15-20 seconds before it finds and loads the page.

The solution has been to remove the DNS setting mentioned above and go back to full DHCP settings, so I suppose the problem lies in DNS or DHCP setup somewhere, but I don't want to recreate the slow logon problem.

I would appreciate any help or pointers to good sources of easy-to-understand information. I did my MCSE, but it was 4 years ago and it is in NT4 anyway, and I havent touched DNS since we migrated 2 years ago.

Thanks

 

That sounds like a job for a packet sniffer. Install Ethereal on the problem PC and use it to watch the network traffic. On opening a new website on the PC you should see a burst of DNS traffic, followed by a longer burst of HTTP.

If it takes a long time before you get the first burst of DNS, then I'd look for a source for the problem in Windows.

If you get BOOTP or DHCP traffic first, DHCP would be the likely problem. (I'd be surprised if you saw this)

If DNS takes any longer than a couple of seconds, look at DNS. Analysising the packets may give you a lead as to the source of the problem - for example the system first going to one DNS server, failing and then looking for a second.

If HTTP takes a lot of time, I'd look at your browser and proxy settings. Also see if it is a problem with a particular site.

In pragmatic mode - If I was you I'd set up a static IP settings on you CEO's PC! I presume you've already connected his PC directly to the network core switch like any other BOFH.