Example of saving iptables firewall rules in Ubuntu

Save iptables rules under ubuntu and automatically load them at boot time:

Saving iptables Save settings

After the machine restarts, the configuration information in iptables will be cleared. You can save these configurations and let iptables load automatically at startup, saving you from having to re-enter each time. Iptables-save and iptables-restore are used to save and restore settings.

Configuration onstartup Boot Autoload Configuration

Save firewall rules to /etc/iptables.up.rules file first

# iptables-save > /etc/iptables .up.rules #requires sudo su - root to switch users after execution, directly sudo cmd is not working

Then modify the/etc/network/interfacesscript to apply the rulesautomatically (the bottom line is added)

Then modify the script /etc/network/interfaces so that the system can automatically apply these rules (the last line is manually added by us).

auto eth0

iface eth0 inet dhcp

pre-up iptables-restore < /etc/iptables.up.rules

When the network interface is down After that, you can have iptables use a different set of rules.

auto eth0

iface eth0 inet dhcp

pre-up iptables-restore < /etc/iptables.up.rules

post-down iptables -restore < /etc/iptables.down.rules

Tips Tips

If you frequently edit iptables manually

Most people don’t need to change their firewall rules often Therefore, as long as the previous introduction, the firewall rules can be established. But if you want to change the firewall rules frequently to make it more complete, you may want the system to save the firewall settings before each reboot. To do this, you can add a line to the /etc/network/interfaces file:

pre-up iptables-restore < /etc/iptables.up.rules

post-down iptables-save > /etc/iptables.up.rules

The line "post-down iptables-save > /etc/iptables.up.rules"will save the rules to be used on the next boot.< Br>

"post-down iptables-save > /etc/iptables.up.rules" will save the settings for use at the next startup.

Usingiptables-save/restore to test rules Using iptables-save/restore to test rules

Using iptables-save and iptables-restore makes it easy to modify and test firewall rules. First run iptables-save to save the rule to a file and then edit the file with an editor.

# iptables-save > /etc/iptables.test.rules

# gedit /etc/iptables.test.rules

If you built it according to the previous example Firewall rules, iptables-save will produce a file similar to the following:

# Generated by iptables-save v1.3.1 on Sun Apr 2306:19:53 2006

*filter

:INPUT ACCEPT [368:102354]

:FORWARD ACCEPT [0:0]

:OUTPUT ACCEPT [92952:20764374]

-A INPUT - m state --state RELATED,ESTABLISHED -j ACCEPT

-A INPUT -i eth0 -p tcp -m tcp --dport 22 -j ACCEPT

-A INPUT -i eth0 -p Tcp -m tcp --dport 80 -j ACCEPT

-A INPUT -i lo -j ACCEPT

-A INPUT -m limit --limit 5/min -j LOG --log -prefix"iptables denied: " --log-level 7

-A INPUT -j Drop

COMMIT

# Completed on Sun Apr 23 06:19:53 2006

The contents of the file are actually various iptables commands, except that the command name iptables is omitted. Feel free to edit this file and save it. Then test the modified rules with the following command:

# iptables-restore < /etc/iptables.test.rules

Before you added the /etc/network/interfaces file The iptables-save command, after the test, don't forget to save your changes.

# iptables-save > /etc/iptables.up.rules

Added: Backup and restore of iptables firewall rules

First, save iptables rules to a file # Sudo iptables-save > /etc/iptables.up.rules

Then, modify the /etc/network/interfaces script to automatically apply these rules (the last line is added) sudo echo "pre-up iptables- Restore < /etc/iptables.up.rules" >> /etc/network/interfaces

You can also prepare a set of rules to apply it automatically:

First, save the iptables rules Go to a file # sudo iptables-save > /etc/iptables.up.rules Then, modify the /etc/network/interfaces script to automatically apply these rules (the last line is added)

sudo echo "pre -up iptables-restore < /etc/iptables.up.rules" >> /etc/network/interfaces You can also prepare a set of rules to apply it automatically:

sudo echo " pre-up Iptables-restore < /etc/iptables.up.rules" >>/etc/network/interfaces sudo echo "post-down iptables-restore < /etc/iptables.down.rules " >> /etc/network/interfaces

The above method has been tested in Ubuntu 12.04 and is in effect.

sudo echo " pre-up iptables-restore < /etc/iptables.up.rules" >>/etc/network/interfaces sudo echo "post-down iptables-restore < /Etc/iptables.down.rules " >> /etc/network/interfaces The above method has been tested in Ubuntu 12.04 and is in effect.