Which ports are accessible through unkown routers/NATs?

Onion Avenger

Hello,

At the university I'm at, I can SSH into my box anywhere from on-campus. All is peachy. But off-campus, it times out. I tried FTP and that times out, as well. I'm sure they're making extensive use of routers and NATs and such. Networking isn't really my thing, so I can't say for sure.

Anyway, I need to find some ports that _ARE_ open to the outside world. Is there a way where I can open up all my ports then nmap my computer from the outside? Is this the best way? I'd only leave my computer in such a state for a day or less, so I'm not too worried about security risks.

Any pointers would be great!
Thanks,
--Richie, the Onion Avenger

Onion Avenger · Posted: Fri Oct 17, 2003 4:59 am Post subject:

Oh, and by the way, I already asked the Office of IT this and the secretary or something basically told me I'm on my own on this. I'm sure I could easily talk to somebody higher up there that knows the answer to my question, but I think it'd be more fun to just do it myself. Never know when I might need to do this in the future...

malloc · l33t Joined: 19 Sep 2003 Posts: 762

Well it looks they drop all incoming ssh traffic from outside. If that's the case there isn't a lot you can do. Maybe you can use another port wich you know to be open and get the sshd to run in it.

PS - Just re-read your post and it looks like they have all outside incoming traffic blocked. So i guess you're out of luck

professorn · Posted: Fri Oct 17, 2003 2:45 pm Post subject:

Port scan and check for open ports? But how your goning to redirect it to your machine I don't know

Onion Avenger · Posted: Fri Oct 17, 2003 3:50 pm Post subject:

malloc - yeah, but the thing is I need to find a port that _is_ open. I don't know which ones are. Obviously not 22 and 21 since I tried SSH and FTP.

professorn - ahhh good point. My IP address is 10.7.226.* so isn't this in a private range? But my machine resolves like this on the DNS. If I ping or do whatever (from off-campus or on) onion-station.rn.byu.edu it will give me this IP (10.7.226.x) However, ping doesn't do more than resolve my IP since they've turned off ICMP until all the virii running around subside or something.

SpinDizzy · Posted: Sat Oct 18, 2003 2:47 am Post subject:

Yes, that IP address is in a private range, which means it is only accessable from another machine in the same range (ie: on campus), even though the address itself is given by the DNS servers.

For external access, you need someone to reprogram their (the campus's) border router to port forward a specific port on that router to that private IP.