MSN Messenger File Transfer Problem

[henryd_il]

I'm having trouble debugging a file transfer problem.
My setup is as follows:

Computer A is WinXP running Windows Messenger 4.7
Computer B is WinXP running Windows Messenger 4.7 + Kerio Firewall
Computer C is Win98 running MSN Messenger 6.2 + Kerio Firewall

File transfers between A & B are fine
File transfer between A & C are fine
File transfers between B & C always fail with the message 'file transfer timeout' that occurs immediately after B accepts a file from C.

What I fail to understand is that if mixed OS/Messenger such as between A & C works, why does the same mix between B & C fail.

Suspecting a firewall config issue I deleted all Messenger,Internet Explorer and Outlook Express entries from the Kerio instalation on machine C.
After firing up Messenger on C, Kerio then alerted me with all connection requests by Messenger which I permitted.
After this excersize transfer between A & C worked but not between B & C.

[Deadeye]

Instead of permitting access, did you try disabling firewall?

[henryd_il]

No, I didn't turn off the firewall for reasons of simple survival.
A glance at my firewall log shows that my machine is under constant attack. I'd rather not take the chance.

[Deadeye]

99% of what you see as attacks are not really attacks, relax. I get many of those ''attacks'' too. If you had to send a small file through MSN I guess you could disable it for a few seconds. No one will hack you if you let your guard down for that little time.