Port Question

So, I'm running a piece of software that's connected to a remote service and communicating information. I can also connect to this remote service with Telnet and communicate that way manually. It would be nice to have the software running and have telnet on the same "session" such that I can debug exactly what's going on and interact with it. Is there a way "split" a port like that? I've tried doing tricky things with PuTTY but not sure where that's going, or if there's an easier way. Much appreciated!

I'm not sure about "splitting the port", but if you might try running wireshark or tcpdump while connected. Then you'd have the packets and can look at it that way. Won't give you the ability to be interactive tho.

Yeah, I'm looking for more than just being able to see the packets though. Being able to see and respond in a live session will open up lots of doors, and in some cases could eliminate needing to create a false client to do testing, things like that. This seems like a particularly useful task (especially concerning vulnerability assessment), I've been surprised how little I can dig up. Looking for more ideas, I'll post if I figure anything out.

I see no technical reason why this couldn't work. Ports are only allowed to be bound once (correct me if I'm wrong), but I don't see why that data couldn't be forwarded to two applications and vice-versa have both respond back.

Ports are the way that the packets know which application the incoming packets are destined for. Read up more on the TCP/IP Stack man. That is where you will be able to get your real information about "port sharing".

That being said, Browsers and MSN work off the same port (hint hint)

Thanks for the replies!

I think I'm going to go ahead and write the application, lots to be learned at the least. I'll post the source back here when I'm done (assuming things go well, and I have time to finish).

And yep, I've done a bit of socket programming before, I might tackle this project with PHP. I wrote the game server in PHP (which is the "service" I'm analyzing, was just trying to make my post as quick as possible), so I've got a lot code I can work with already.