How do I edit Iptables?

Dmjmusser · 12-28-2005, 10:03 AM

Iptables is preventing me from using a monitoring service called Nagios to monitor local services (processes, disk space) on a remote host. The reason is that the Iptables on this remote host are set to only allow traffic through on port 25, and I need to dedicate another port to allow this traffic through (specifically, I'd like to use 5666). Additionally, I'd like for this remote host to only allow traffic on that port from machines on the company LAN. I'm just not sure how to go about doing this; I don't even know what commands I would use to get this started. Any help would be so greatly appreciated.

~Myles

tuxrules · 12-28-2005, 10:21 AM

Quote:

Originally Posted by Dmjmusser

Iptables is preventing me from using a monitoring service called Nagios to monitor local services (processes, disk space) on a remote host. The reason is that the Iptables on this remote host are set to only allow traffic through on port 25, and I need to dedicate another port to allow this traffic through (specifically, I'd like to use 5666). Additionally, I'd like for this remote host to only allow traffic on that port from machines on the company LAN. I'm just not sure how to go about doing this; I don't even know what commands I would use to get this started. Any help would be so greatly appreciated.

~Myles

Do you use a gui or script to run iptables? What protocol does your monitoring service use?

I am assuming you use tcp. If you are using a script you can add something like this in your script.

Code:

/usr/sbin/iptables -A INPUT -i eth0 -p tcp -s 192.168.1.0/24
--dport 5666 -j ACCEPT
/usr/sbin/iptables -A OUTPUT -o eth0 -p tcp --sport 5666 
-d 192.168.1.0/24 -j ACCEPT

obviously, you have replace eth0 with whatever is your interface. Also you would have to replace the network address to fit what you have.

Dmjmusser · 12-29-2005, 10:22 AM

Okay, I entered in those commands (well, modified a bit to fit my circumstances). Do I need to do something that will cause this new rule to take affect? After I added the rule, I executed iptables -L, but the new rule does not show there.

-Myles

Dmjmusser · 12-29-2005, 11:54 AM

Quote:

Originally Posted by Dmjmusser

Okay, I entered in those commands (well, modified a bit to fit my circumstances). Do I need to do something that will cause this new rule to take affect? After I added the rule, I executed iptables -L, but the new rule does not show there.

-Myles

Hah...forget it, I figured out how to restart Iptables. But the rule I entered didn't stick. I wonder why. Mayhap I should post it and someone can help me troubleshoot?

~Myles

ssfrstlstnm · 12-29-2005, 01:07 PM

Shorewall = iptables made easy (not that is was that hard to begin with)

wrj · 12-29-2005, 01:20 PM

try iptables-save to write it to the file fedora uses. I don't know which file it is because I've never used fedora, but I'm sure others can help you with that.

"man iptables-save" for more info