TCP port shows as closed, but no firewall

jnojr · 02-18-2010, 06:39 PM

nmap is showing a port as closed. I have the firewall stopped on both hosts. It shows as closed on localhost as well. The process that's listening to that port is not started from xinetd so i doubt hosts.allow/deny is the issue. I can't help but feel that I'm forgetting some other access control mechanism. Both hosts are RHEl5.4

paulsm4 · 02-18-2010, 06:58 PM

Hi -

1. Definitely focus on getting it to work on "localhost" first.

2. I assume this is probably a TCP port (rather than UDP). If so, you can use "telnet localhost PORT#" to check connectivity. Taking a wireshark trace might also be helpful.

3. Yes, your firewall/iptables is definitely the first thing to look at.

Perhaps SELinux might be the second thing to look at.

4. In any case, these links might help:
http://www.linuxforums.org/forum/red...ing-ports.html

http://www.linuxtopia.org/online_boo...ch-server.html

Please post back what you find!

jnojr · 02-18-2010, 07:14 PM

Quote:

Originally Posted by paulsm4

Perhaps SELinux might be the second thing to look at.

Screw me, that's probably it.

Always Blame SElinux.

Tinkster · 02-18-2010, 07:16 PM

Well ... the first thing will always be:

netstat -an | grep <port in question>

to see whether the process is actually up & running.