List of loaded iptables modules

Loaded iptables modules can be found in /proc/net/ip_tables_matches proc filesystem entry.

cat /proc/net/ip_tables_matches

In PHP I can access the loaded iptables modules by loading and exploding file contents:

$content = file_get_contents('/proc/net/ip_tables_matches');
$modules = explode("\n", $content);

Of course it requires proc filesystem to be mounted (Most GNU Linux distros mount it by default)

As an alternative method, this can also be done with a Python script.

First make sure you have the iptc library. sudo pip install --upgrade python-iptables

(Assuming Python3 is your version)

import iptc
table = iptc.Table(iptc.Table.FILTER)
for chain in table.chains:
    print("------------------------------------------")
    print("Chain ", chain.name)
    for rule in chain.rules:
        print("Rule ", "proto", rule.protocol, "src:", rule.src, "dst:" , rule.dst, "in:", rule.in_interface, "out:", rule.out_interface)
        print("Matches:")
        for match in rule.matches:
            print(match.name)
        print("Target:")
        print(rule.target.name)
print("------------------------------------------")