Debian Firewall unknown

claforce · 06-09-2014, 10:30 AM

Hello,
I'm trying to open up a specific port on a Debian 7.3 system, but I cannot figure out what the server is using for a firewall. iptables -L returns nothing, but I get refused when trying to use the port so there must be a firewall. nmap shows a handful of open ports. Can anyone point me in the right direction here. Let me know what I can offer for more information.
Thanks,

Chris.

szboardstretcher · 06-09-2014, 11:06 AM

"when trying to use the port" means what specifically? What are you trying to do, on the command line, or wherever, that is causing the message. and what is the exact message?

claforce · 06-09-2014, 11:15 AM

So I tried to use nc to listen on port 1270 for testing. See below:

Code:

nc -l IPADDRESS 1270

Then from a different pc:

Code:

nc -vz IPADDRESS 1270
nc: connect to IPADDRESS  port 1270 (tcp) failed: Connection refused

Although port 22 works:

Code:

 nc -vz IPADDRESS 22
Connection to IPADDRESS 22 port [tcp/ssh] succeeded!

Let me know if there is anything else I can provide.
Thanks,

Chris.

szboardstretcher · 06-09-2014, 11:32 AM

Is there a physical firewall between the two computers? are they on a switch together?

Traceroute between the two just in case?

Run TCPdump to see if the packet is getting filtered before reaching the destination NIC?