Debian-Jessie: How do you check iptables status?

Question

In old sysvinit I would just do service iptables status and see if it was running or not.

But in newer Debian-Jessie I grep for iptables in the list of services and don't see iptables listed anywhere. And when I try to query the status via systemctl status iptables I get an error.

Debian-Jessie: How do you check iptables status?

Answer 1

Iptables in Linux is implemented as a number of kernel modules. Normally it is configured by some init script - but you can add and remove rules on the fly from the command line. So basically, there are (at least) thee relevant questions:

• Are the kernel modules loaded?
• Are any rules applied?
• Is my firewall script/program "running"?

The old iptables "service" was obsoleted by systemd. I think this project attempts to make a similar "service" available for Debian.

To see if the kernel modules are loaded:

# lsmod | grep ip_tables

To see the effective rules:

# iptables -L

or, if you want to see the NAT rules:

# iptables -t nat -L

In Debian there are a number of firewall packages that can set up the iptables rules for you. (I have not tried any of them, I usually roll out my own when I need it).

apt-cache search firewall | grep firewall | less