Ports Blocked

spaceballs · 05-02-2005, 07:09 PM

I am using Slackware-Current with linux version 2.6.11. My question is this: I am living in a building with an internet connection out of the wall. I don't know what sort of network that it is. or if it is a modem, T1, etc.

I am unable to use a lot of my applications that use nonstandard ports. SSH, telnet, torrents, etc. What I am trying to find out is this: is it my slackware dist. that is blocking theseports on some sort of security tool that I have activated? Or is it the firewall I might be behind? How can I tell?

Matir · 05-02-2005, 07:20 PM

Well, essentially, you'll need to run some sort of network sniffer to check what is happening to your packets. IF you have an internet connection that is blocking ports such as SSH and the like, I would complain LOUDLY. Internet connections are supposed to provide access, not restrict it.

Also, run 'iptables -L' as root and print the output here, please.

spaceballs · 05-02-2005, 07:23 PM

#iptables -L

Chain INPUT (policy ACCEPT)
target prot opt source destination

Chain FORWARD (policy ACCEPT)
target prot opt source destination

Chain OUTPUT (policy ACCEPT)
target prot opt source destination

What does this mean?

Is it possible that my machine has its own firewall? Or is it more than likely a network firewall?

Tinkster · 05-02-2005, 08:05 PM

That means that your machine allows everything.
No filter-rules defined what-so-ever.

Cheers,
Tink

Matir · 05-02-2005, 09:42 PM

More than likely, it seems to be a network firewall by virtue of you lacking a firewall. Try telnetting to some SSH server at port 22 and see if you get any response at all.