SQL server default instance listen on port number 1433. You can tell SQL server not to listen on this port and listen to another port.

Open SQL server configuration manager, find your instance and follow below steps as shown in figure. MS SQL server default port is 1433.

 
   After changing the default port settings you need to restart the instance.

To let your application talk to sql server on updated port, you need to do little modification at connection string (server=IPaddress,port number)

e.g.
 
 connectionString = "server=192.168.1.1,1477;user=sa;password=pass;database=aspnetdb"

If you want not alter your application configuration settings stored inside web.config file or in application itself,
you need to reroute the trafic from 1433 to update port 1477 using Sql server client network utility (Cliconfg)
you can refer http://www.revenmerchantservices.com/post/2010/01/05/cliconfg.aspx

Execute Netstat -an command from command prompt to know how communication is set betwwen your server and client

Satalaj