The trouble is: i do winsock simple server
socket(), bind(), listen() etc... everething works ok Im myself CAN connect to its port from telnet or IE just my IP and port a.b.c.d:port
But my friend uses another ISP and he CANT connect to it.
When Im online I have IP a.b.c.d and doing telnet on smtp servers after helo they answers that my IP is e.f.g.h. Which one of them real. Does it matter that my friend cant reach me in case that my IP a.b.c.d matters only in my ISP area, and we all get online throu e.f.g.h?
Posted on 2004-09-19 15:11:45 by 9ine
Please give the IP addresses. It seems you maybe behind a firewall doing a NAT of the IP address.

i.e. local IP behind NAT is 192.168.100.XXX, which is the one you can telnet local to. On the outside of NAT, it will what ever the firewall decide to give it. If it's server, you may need to have the firewall adjusted to NAT the same address all the time.

Regards, P1 8)
Posted on 2004-09-21 13:13:13 by Pone
Concerning to the installed network adapters and gateway/router settings your machine is multi-hosted, means it got several ips, one for each adapter / area. There are some example codes on the inet that show how to list all ips, else goto cmd and type ipconfig. The ip that is your internet one can be easily determined by visiting If you are behind a gateway / router the ip address given by might be the one from the gateway/router and not yours. You have to compare it with all ips your system has.
In order to access systems via inet without calling your friend, telling him your ip you can do the following:
- use ICQ, convert your UIN to IP at your friend's system
- use to have a fixed dns name for your machine... this one can be resolved and when your system is online, you can get your ip from at your friends pc....
Posted on 2004-09-21 14:10:38 by Dom
How about port forwarding or port triggering guys? Actually if you can port trigger, try that first. This way, when you run your winsock app, the firewall will take packets sent in from the net destined for that particular port. It's better than port forwarding cause when your winsock app isn't running, the firewall won't be leaving that port open. Leave that port open and people can attack the firewall itself.
Posted on 2004-10-10 00:29:49 by Al_Leitch
my net addr and for IP only last 2 figures changed.
What about ftf connection? servers can connect on my IP but I tell them that send data to 4000 and begin listen on it 'port 172,19,x,x 15,160' and data is sent to me but in winXP pfirewall.log:
openinbound ftf.serverIP 172,19,x,x 20 5001
close ftf.serverIP 172,19,x,x 20 5001
why port 5001?
Posted on 2004-11-08 09:01:27 by 9ine