What is the difference between ServerName and ServerAlias in apache2 configuration?

Question

I am configurating my apache2 server and I wonder whats the difference between ServerName and ServerAlias.

Is the ServerName always a name without www as like goo

Answer 1

From the Documentation:

ServerName: Hostname and port that the server uses to identify itself

ServerAlias: Alternate names for a host used when matching requests to name-virtual hosts

Most people simply use ServerName to set the 'main' address of the website (eg. 'mywebsite.com') and ServerAlias to add additional addresses the website will be bound to (eg. 'www.mywebsite.com').

Yet, there are subtle differences between the two:

• ServerName can accept port numbers as well, while ServerAlias cannot.
• ServerAlias can accept wildcards (eg. *.mywebsite.com), while ServerName cannot.

Read the documentation to understand why.