netstat shows tcp6 for apache server process on linux

Question

Following is output of netstat -tulpn on my linux box. I am running one website on apache on this box. Some networks are not able to connect to my website. Does anyone know if it can be related on tpc6 in output below ? What is significance of it ?

Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name
tcp        0      0 0.0.0.0:53137           0.0.0.0:*               LISTEN      4573/skype      
tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN      748/sshd        
tcp        0      0 127.0.0.1:631           0.0.0.0:*               LISTEN      1054/cupsd      
tcp        0      0 127.0.0.1:3306          0.0.0.0:*               LISTEN      990/mysqld      
tcp        0      0 127.0.0.1:11211         0.0.0.0:*               LISTEN      974/memcached   
tcp6       0      0 :::80                   :::*                    LISTEN      1111/apache2    
tcp6       0      0 :::22                   :::*                    LISTEN      748/sshd        
tcp6       0      0 :::5900                 :::*                    LISTEN      1599/vino-server
udp        0      0 127.0.0.1:11211         0.0.0.0:*                           974/memcached   
udp        0      0 127.0.0.1:53858         0.0.0.0:*                           4573/skype      
udp        0      0 0.0.0.0:5353            0.0.0.0:*                           770/avahi-daemon: r
udp        0      0 0.0.0.0:53137           0.0.0.0:*                           4573/skype      
udp        0      0 0.0.0.0:59303           0.0.0.0:*                           770/avahi-daemon: r

Answer 1

:::80 is the same as 0.0.0.0:80 in IPv4, apache is listening on Inet6 and Inet4.

http://en.wikipedia.org/wiki/IPv6 is a good place to start

Consider getting yourself a tunnel @ http://tunnelbroker.net and playing with the next stage of the internet! It is the future!

Answer 2

That just means that your Apache is listening to both IPv4 and IPv6. Should not be related to your problem at all.