Find Blocked Ports on Network

artielnx · 09-30-2004, 02:23 PM

Right now I'm on a college dorm residential network and certain programs (such as IRC and p2p programs) do not work because their ports have been blocked. I *think* there is some sort of proxy server that separates the dorm network from the internet, I am probably wrong. Is there a way to scan the proxy server (assuming that's what it is) and find out what other ports they have blocked?

I called and asked them this very question, but they didn't tell me anything, and I'm just curious to see what other ports they blocked so I know. One thing I do not know is the IP address of the proxy server. How do I find that out?

I've been messing around with nmap a bit, but I really have no idea what I'm doing lol. Appreciate any help.

Tinkster · 09-30-2004, 02:56 PM

The "proxy" (which is quite likely to be a router
and/or firewall as well) will probably be what
route
gives you as the default gateway...

But you REALLY should make sure that network
scans aren't a punishable offense on your network,
if I were a sys-admin there and you scanned my
network I'd exclude your machine from ANY traffic
for some time ;)

Cheers,
Tink

Joey.Dale · 09-30-2004, 03:01 PM

To find the proxy server, do

Code:

traceroute yahoo.com

You will get something like

Code:

 1  10.103.160.1 (10.103.160.1)  12.203 ms  8.079 ms  8.273 ms
 2  atm2-0-622.tampflerl-rtr1.tampabay.rr.com (24.92.7.102)  10.090 ms  13.845 ms  9.076 ms
 3  pos13-0.tampflerl-rtr3.tampabay.rr.com (65.32.8.2)  10.357 ms  9.325 ms  10.227 ms
 4  pop1-tby-P0-1.atdn.net (66.185.136.169)  12.345 ms  12.330 ms  11.018 ms
 5  bb1-tby-P0-0.atdn.net (66.185.136.160)  29.359 ms  9.782 ms  10.186 ms
 6  bb2-atm-P7-0.atdn.net (66.185.152.245)  31.984 ms  28.426 ms  28.032 ms
 7  pop1-atm-P1-0.atdn.net (66.185.147.195)  30.539 ms  26.842 ms  28.063 ms
 8  if-8-0.har1.Atlanta3.teleglobe.net (64.86.9.1)  29.325 ms  27.303 ms  28.138 ms
 9  if-0-1.core1.Atlanta3.Teleglobe.net (64.86.8.5)  34.604 ms  27.340 ms  27.978 ms
10  if-2-3.core1.Dallas3.teleglobe.net (66.198.1.17)  84.913 ms  82.347 ms  86.442 ms
11  if-0-0.core2.Dallas3.teleglobe.net (66.198.1.2)  92.306 ms  83.056 ms  82.458 ms
12  ix-5-0.core2.Dallas3.teleglobe.net (66.198.2.14)  83.983 ms  83.460 ms  83.014 ms
13  vl151.pat2.pao.yahoo.com (216.115.96.40)  87.979 ms  85.077 ms  84.645 ms
14  vl35.bas1-m.scd.yahoo.com (66.218.82.197)  85.300 ms vl16.bas1.scd.yahoo.com (66.218.64.146)  86.133 ms vl35.bas1-m.scd.yahoo.com (66.218.82.197)  85.498 ms
15  vl44.bas1-m.scd.yahoo.com (66.218.82.234)  85.835 ms UNKNOWN-66-218-82-230.yahoo.com (66.218.82.230)  85.422 ms vl44.bas1-m.scd.yahoo.com (66.218.82.234)  86.624 ms

The last local address is the proxy

local addresses start with 10 or 192.
Good Luck

-Joey