The Address field contains the base address that this listen socket is listening on. It contains the IP address and the port number.
If your listen socket listens on all IP addresses for the machine, the IP part of the address is 0.0.0.0.
This setting is tunable when you edit a listen socket. If you specify an IP address other than 0.0.0.0, the server will make one less system call per connection. Specify an IP address other than 0.0.0.0 for best possible performance.
For more information about adding and editing listen sockets, see the Sun Java System Web Server 6.1 SP6 Administrator’s Guide.