Debian / Ubuntu: Apache2 Change Default Port / IP Binding

Question: How do I change Apache 2 default port under Debian / Ubuntu Linux? I've couple of public IPv4 address assigned by my ISP, how do I force Apache2 to listen to a specific IP address? How do I change Apache2 IP address binding?

Answer: You can easily change the port and other settings using following directives:

Apache Listen Directive

The Listen directive instructs Apache to listen to more than one IP address or port; by default it responds to requests on all IP interfaces, but only on the port given by the Port directive. You can use this directive multiple times.

Task: Change Apache port

Open /etc/apache2/ports.conf file, enter:
# vi /etc/apache2/ports.conf
OR
$ sudo vi /etc/apache2/ports.conf
To make the server accept connections on both port 8010, enter:
Listen 8010
To make the server accept connections on both port 80 and port 8010, use:
Listen 80 Listen 8010

Task: Accept connections on specific IP / interface port

You need to use network interfaces IP address. For example, to make the server accept connections on IP 202.54.1.2 and port 80, enter:
Listen 202.54.1.2:80
To make the server accept connections on two specified interfaces and port numbers, enter:
Listen 202.54.2.1:80 Listen 202.54.2.5:8010
Save and close the file. Restart Apache 2 webserver:
# /etc/init.d/apache2 restart
OR
$ sudo /etc/init.d/apache2 restart

How do I verify port and IP binding working ?

Use netstat command to find out if Apache is listening on a specific port or not, use:
# netstat -tulpn # netstat -tulpn | grep :80 # netstat -tulpn | grep :8010 # netstat -tulpn| grep 202.54.1.2:80
Sample output:

tcp        0      0 202.54.1.2:80            0.0.0.0:*               LISTEN     19306/apache2