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Click to See Complete Forum and Search --> : ["RESOLVED"] UDP connection blocked by WindowsXP?

opus
Mar 11th, 2007, 11:41 AM
Hi I have a lan-application that is using TCP and UDP connections. I have them all running on a win98 network. For testing purposes I use the loopback IP and run them all on one computer, no problem on a win2000 machine.
The problem started when I tried to test on a XP machine, the connectioon to one "client" is working (all connections TCP and UDP) whereas the connections to other "clients" are limited to the TCP connections?
Does anybody know of issues concerning XP and UDP?
Lozzenger
Mar 12th, 2007, 08:11 AM
It might be due to the fact you're using the loopback address

I've had problems using that address before so in the end I had to use my LAN computers address
opus
Mar 12th, 2007, 08:33 AM
Thanks for the hint, I'll give it a try! (When I'm on my HomePC again)
rnd me
Apr 2nd, 2007, 09:04 PM
Hi I have a lan-application that is using TCP and UDP connections. I have them all running on a win98 network. For testing purposes I use the loopback IP and run them all on one computer, no problem on a win2000 machine.
The problem started when I tried to test on a XP machine, the connectioon to one "client" is working (all connections TCP and UDP) whereas the connections to other "clients" are limited to the TCP connections?
Does anybody know of issues concerning XP and UDP?

xp and 2k should have compatible stacks.
i would suspect a XP SP2 windows firewall.

try disabling the personal firewall on your xp machine.
DigiRev
Apr 2nd, 2007, 11:04 PM
I don't think the XP firewall blocks local access connections (especially to the loopback address (127.0.0.1/localhost?).

I would still disable the firewall and try again.

Uploading your project or attaching some code wouldn't hurt if that doesn't fix the problem. ;)
opus
Apr 3rd, 2007, 12:23 AM
The XP firewall is "noticing" the lan-connection (even on local-host) and is therefore asking for permission, but only sometimes????. In the present state I can get to connection to 1 of the 5 clients (and all are using the same .exe). I'm lost on this one, but since the main application is running on a win98 lan, and running well, let us forget about that one.
I'M closing this threat, Thanks everybody!