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How to set up Ubuntu14.04 firewall

Posted on 2015-03-27 In Linux

Ubuntu does not start any firewall in default, so we had better set up some rules for the network in case of any safety issues. The following will make a short introductions about how to set up the iptable for ubuntu.

1. Check whether the iptables is installed

1 2	root@ubuntu14:~# whereis iptables iptables: /sbin/iptables /etc/iptables.rules /usr/share/iptables /usr/share/man/man8/iptables.8.gz

2. Check the iptables rule

root@ubuntu14:~# iptables -L
Chain INPUT (policy ACCEPT)
target     prot opt source               destination         
ACCEPT     all  --  anywhere             anywhere             state RELATED,ESTABLISHED
ACCEPT     icmp --  anywhere             anywhere            
ACCEPT     all  --  anywhere             anywhere

3. Edit the iptables rule

root@ubuntu14:~# nano /etc/iptables.rules 
# Firewall configuration written by system-config-firewall
# Manual customization of this file is not recommended.
*filter
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
-A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
-A INPUT -p icmp -j ACCEPT
-A INPUT -i lo -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp --dport 22 -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp --dport 5000 -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp --dport 8080 -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp --dport 80 -j ACCEPT
-A INPUT -j REJECT --reject-with icmp-host-prohibited
-A FORWARD -j REJECT --reject-with icmp-host-prohibited
COMMIT

4. Make the new iptables rules work

1	iptables-restore < /etc/iptables.rules

5. Enable the iptables be launched once OS starts

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vi /etc/network/if-pre-up.d/iptables
#!/bin/bash
iptables-restore &lt; /etc/iptables.rules

6. Enable the script be executable

1	chmod +x /etc/network/if-pre-up.d/iptables

7. Check the iptables rule

1	iptables -L -n