I have a Win XP Pro PC on our corporate network which does not respond to pings or any other traffic initiated from any other PC. (Request Timed Out.)
Any traffic initiated from the PC itself works perfectly fine. It can surf, ping and the whole works.
At first it seems like a simple matter... "Must be a firewall!!! "
Not so fast! :D
The user can send Instant Messages with windows Messenger and i receive them, but if i type something back, it is just rejected.
I cannot netmeeting into the machine, so the user called me with netmeeting, and then shared his desktop (once again proving oneway communication)
When i connected to the machine i checked the Builtin Windows Firewall setting - Which is disabled.
I also suspected a common desktop firewall package named BlackICE - Which is also NOT installed on the machine.
I did not find any other suspicious software, but i continued to do the following:
I started a continous ping from my machine to the user's machine - Request Timed out constantly.
Then i started to, one by one, kill all tasks in Task Manager until i was left with only the basic core Windows XP tasks... still no reply from the PC.
I suggested to the user that we will have to re-image his PC which he agreed to, but i do not beleive that this can be the only solution. Before i do that i want to get to the root of this problem.
I rebooted his pc while leaving the ping running on my machine, and while its rebooting i get a total of 6 replies on the ping, before it is blocked again.... (probably just after networking was initialised and just before the stupid piece of software started interfering)