Tech Support > Microsoft Windows > Networking > Firewall detects local Port access, but Port hasn't been forwarded by Router
Firewall detects local Port access, but Port hasn't been forwarded by Router
Posted by iceman on December 6th, 2005


Hi,

I recently got some good help in these groups regarding switch to NAT / Port
Forwarding.

I've setup some Port Forwards for a couple of local services.

However, what I've noticed is that if I watch my Firewall logs (ZoneAlarm),
I can see ZA blocking connection attempts on a UDP port that I haven't
forwarded from my Netgear Router.

My question is, why is this connection attempt being forwarded by the Router
to the laptop behind the router (and on a 192.168 address)? I understood
that attempts to connect to ports that AREN'T forwarded would just be
filtered out by the Router. This looks like it's being passed through to my
laptop.

Am I misunderstanding NAT / Port Forwarding?

Cheers

iceman


Posted by Dom on December 6th, 2005


Please provide more information concerning the nature of the traffic,
especially destination and source IPs and ports.

Posted by iceman on December 6th, 2005


I think it's to do with Azureus. I have configured port forwarding for a
number of Azureus ports (6881 - 6889 UDP).

However, if I watch Zone Alarm alerts and logs, a number of attempts are
made to connect to port 2081 UDP on my 192.168... laptop. I haven't
forwarded 2081 in my Router. There's a variety of source IPs, some using
port 6881.

I can't understand why if the port has not been forwarded from the router,
Zone Alarm can detect connections being made.

The only other port forwarding I've got is a web/ftp server, and netmeeting.

iceman

"Dom" <invalid@invalid.invalid> wrote in message
news:43962de0$0$23953$892e7fe2@authen.yellow.readf reenews.net...
> Please provide more information concerning the nature of the traffic,
> especially destination and source IPs and ports.



Posted by Dom on December 7th, 2005


This sounds like response traffic to your own outbound traffic. Do a
netstat -a to see if the laptop is listening for udp on 2081.

Posted by iceman on December 8th, 2005


Thanks for that Dom - I've done an uninstall/reinstall/reboot, and somehow
I'm not getting traffic on this port know.

But I'll keep netstat in mind for the future for other diagnostics.

Thanks again.

iceman

"Dom" <invalid@invalid.invalid> wrote in message
news:43963924$0$42132$892e7fe2@authen.yellow.readf reenews.net...
> This sounds like response traffic to your own outbound traffic. Do a
> netstat -a to see if the laptop is listening for udp on 2081.