A rather interesting problem. There is one server on the network where we can no longer use the web browser to reach sites on the internet. Other servers and desktops work just fine.
This is the server that hosts Exchange server 2000. Ther is no real problem in passing mail other than the usual bad addresses and such, though their is one site that cannot be reached via mail.
The only recent changes were the installation of a spam filter (GFI Mail Essentials for Exchange v. 10) and the browser worked fine after that.
The other change was to modify the internal DNS to provide a path to the mail server of a company that we will be doing a lot of business with over the next year or so. This was done because there was not a proper fail over for the MX record of this firm. I did finally find the proper fix for this, but it has yet to be obtained and fixed. However, the browser worked after this fix was implemented.
On Thursday i found tha tthe browser on this machine would not reach the web. I ran a series of pings by IP address. The internal network is reach able, but pings outside the network time out. If I ping by name to the outside, the proper address is returned, which means the lookup succeeds, but the ping then times out.
Setting the firewall to record all outgoing and incoming attempts to ping so that the ping goes out, but I see no return, so it seems the ping is passing the firewall--remember this is the only machine experiencing this problem.
Since this is the production mail server, I am somewhat limited in being able to bring it down and do anything, or even take it off the network for a time. It had been restarted just prior to this problem with the browser because the mail suddenly stopped flowing. The browser worked fine prior to the restart. The machine appears to be free of virus, but I am not able to update the anti-spyware definitions for spybot, so that has not been run as the machine was clean, and has never shown an infection.
The browser is normally just used to obtain updates for the OS, Exchange Server, etc., so it is unlikely to have an infection of spyware or adware.
I am looking for ideas how to resolve this problem, as we do need to be able to update the server.