Iptables isn't as intimidating as it might first seem. After all, it's just a set of tables, and chains, and rules, and the bare essentials of connecting to your server.

Netfilter, Linux's in-kernel "packet mangling" infrastructure, and iptables, the administrative tool that manages it, represent a substantial improvement over ipchains, the previous option ...

You can use iptables-save and iptables-restore to generate and load one, but it's just as easy to make an /etc/rc.d/rc.firewall script and link it in at the beginning of the /etc/rc.d/rc.inet* chain.

The iptables -L command, by the way, doesn't really show enough info to be useful for troubleshooting. We'd need to see the actual script you're running, at least the parts relevant to SMTP.

Linux's iptables allows powerful firewalls to be implemented at a minute fraction of the cost of many commercial offerings. Basic iptables firewalls are packet filters, which means they inspect the ...

How to Block Multiple IP Addresses on IPTables. When you use IPTables to create a firewall for your company's Web server, one way to prevent certain users from accessing the server is to block ...

Mastering iptables could take a while, but if you have a few rules to cover the basic security needs, you'll be well on your way to protecting your Linux system. Jack Wallen explains some key ...

Most of us think of iptables strictly as a firewall tool for keeping remote attackers at bay. But did you know it also can be used to keep local users in line? The experimental match extension owner ...

Because Docker actually bypasses UFW and directly alters iptables, such that a container can bind to a port. This means all those UFW rules you have set won’t apply to Docker containers.