through the fire!

Hi!

I made a small chat client and chat server program. As we've got here a firewall, I sent the server part to my friend, who sent back his IP, and that way I could establish the connection with his computer. Of course, the client was running on my machine, as he cannot get through our firewall.

But, I tried the same thing with my girlfriend, and it didn't work.
She's got a firewall, too. And I made the whole program to be able to chat with her, when we're at the office.

Hope somebody has a really revolutionary idea, how to connect a remote, when both computers are behind a firewall?

Thanks in advance.

Have a nice code!

My Advice: If your computer is on fire, don't use a bucket of water to put it out.

Just wandering why cant you just give the program permission to use the net in the firewall?, surely your firewall has rules for applications.

Or if you dont want to do it manuelly i guess the firewalls rules have to be stored somewhere? and if they arnt encrypted i guess you could edit them from your program. As another idea you could temporairly disable the firewall from your program as a last resort.

Sorry i cant help more
TNT

Well TNT, most corporations arent keen on changing firewall settings so employees can converse with the g/f on company time. Damn capitalist pigs :p

Could try having a terminal setup (telnet, probably) that both of you could connect in to, establishing two connections through one firewall each rather than one connection through two firewalls, and one in the wrong direction.

Not sure what firewall's you are using but try sending the data on a very high port. Some of the firewalls don't detect packets sent on the upper ports.

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Originally posted by Imperito
My Advice: If your computer is on fire, don't use a bucket of water to put it out.

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If your computer is on fire, use a Class C fire extinguisher to put it out. =)

since you already have the fire, couldn't you just do smoke signals?

if you have access to the web, set up a message board and use that to chat..?

Try fooling it by using a common port that sould not be blocked.

Say for mail or ftp.

Your firewall may have permissions by program or by port number.

Thanks guys for your answers, even for the humorous ones ;°).

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Well TNT, most corporations arent keen on changing firewall settings so employees can converse with the g/f on company time. Damn capitalist pigs :p

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Well, yes, Imperito, you're right! ;°)))

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Could try having a terminal setup (telnet, probably) that both of you could connect in to, establishing two connections through one firewall each rather than one connection through two firewalls, and one in the wrong direction.

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That sounds good, but how? Could you please give me a starting point, reference, etc.? Thanks.

Here is what I've got: port#53 is ok, it's open. I guess it is used by mail server (?).

I put the question another way: how do some chat programs - e.g. ICQ - identify my computer, as it *is* working, even through the firwall?

If I could somehow implement this functionality in my program,
everything would be fine.

But how?

Do you have a chance to place your server in a third, independent place ? Like your home ? This way you should both be able to connect to it, because at home you can configure your firewall as you like it.

For reserved port numbers in windows OS look in 'winsock.h' or better 'winsock2.h'

(53 is not reserved for mail or anything else in winsock.h)

to find if your ports are available try

https://grc.com/x/ne.dll?bh0bkyd2

for an online scanner at Gibson Research corp

Thank you Nvoigt and Novacain.

Nvoigt, I was also thinking that might be a solution: to use a third computer as server.

That's how ICQ works as well, isn't it?