Hii all i am trying to change the port no of my tomcat server installed in ubuntu. for this i have changed the file server.xml and made a change there as:

<Connector port="8081" protocol="HTTP/1.1" 
           connectionTimeout="20000" 
           URIEncoding="UTF-8"
           redirectPort="8443" />

But the problem is that whenever i try to open the localhost:8081 it is working fine but when i tried to open localhost:8080 then it is still accessible. So please explain this why this is happening.

Secondly when i made the default port to 80 then localhost:80 or localhost then it was not accessible. So please explain this why this is happening.

Thanks in advance.