Posts Tagged: iptables

iptables connection tracking table full

Posted by & filed under Linux, Network.

I’ve recently experienced that my workstation (Ubuntu Jaunty Jackalope, 9.04, x86_64) “hangs” periodically when my internet browser, Mozilla Firefox, has a lot of active tabs. In my case I had > 100 active tabs in more than 20 windows. I know I should have closed some of them but that is not an option right [...]

ufw and IP masquerading

Posted by & filed under Linux, Network, Security.

I’ve just upgraded my home server from Ubuntu 8.10 to 9.04 and experienced that my ufw firewall (iptables) would not route traffic from my local network to the Internet. My IP masquerading was not working anymore and since I had not documented the process when I set it up I had to search the Ubuntu [...]

Some iptables tricks

Posted by & filed under Linux, Network.

Multiport The Multiport extension allows you to specify multiple ports and ranges and makes it possible to create complex rules in one line. Here’s an example of how you can allow SSH, Web, IMAP and X terminal traffic iptables -A INPUT -p tcp -m multiport –dports 22,80,143,6000:6003 -j ACCEPT The alternative to using this rule [...]

Using ufw / iptables in Ubuntu 8.04 LTS

Posted by & filed under Linux, Network.

ufw (Uncomplicated Firewall) is a new and easy firewall/iptables tool introduced in Ubuntu 8.04 LTS (Hardy Heron). ufw is a front-end for iptables-restore, with its rules saved in /etc/ufw/before.rules, /etc/ufw/after.rules and /var/lib/ufw/user.rules. Administrators can customize before.rules and after.rules as desired using the standard iptables-restore syntax. Rules are evaluated as follows: before.rules first, user.rules next, and [...]

Getting iptables to survive a reboot

Posted by & filed under Linux, Network, Scripting.

As far as I know Debian doesn’t have any defined way to save your iptables rules. I’ve done it this way: First I’ve made my iptables rules and made sure they work. Second is to save those rules to a configuration file iptables-save > /root/scripts/iptables.save I always try to save my custom scripts and required [...]