I have a Rackshack server, (who another person has helped me admin) and I have just installed ntpdate to synchronize my time settings with an external time server. The problem is that it is not connecting properly. The FAQ indicate the problem might be with my firewall settings, but silly as it may be I don't know if my server has a firewall. Is there some unix command to look for that or do I have to contact rackshack support (or bug my admin helper) and wait until tomorrow?

PortScan it, if everything and your mother is listening then you most likely dont have a firewall, besides firewalls generally dont block outgoing traffic it is more likely that you have it misconfigured.

-Drew

I don't believe that a firewall comes pre-installed on a server at Rackshack. So unless you installed it, it is probably not there.

All linux based servers have iptables (or should) on them. This is a VERY stock linux firewall.

What you're probably referring to is a frontend to the firewall, which makes it easier to manage iptables.

http://forums.ev1servers.net/showthread.php?threadid=22082&highlight=apf

Yes, IP tables does come installed on 99% of Linux distributions, but not configured.

Thanks,
-Drew

Originally posted by nixboxen
Yes, IP tables does come installed on 99% of Linux distributions, but not configured.

Aye, but the question wasn't do I have a configured firewall, it was do I have a firewall ;)

Petty, I know, but it's true, most Linux boxes have some either iptables or ipchains on 'em.

I agree, configuring them without understanding WHAT they are and how they work is a big pain, and can result in some drastic problems.

Just as a rule of thumb, just because you have a poorly configured Iptables installation doesnt mean your box is hardened :P.

-Drew

run this command in SSH:

iptables-save > ./iptables.log

then in iptables.log file you will find all iptables rules and will see if you have anything that blocks connections. If you don't have a firewall, the file will be empty or 3-4 lines/chains with all ACCEPT statements.