First page Back Continue Last page Overview Graphics
Listening Ports
When an application is bound to a port and is listening for incoming connections from any address, your computer is acting as a server
Notes:
On a client machine that should not be providing any services to other hosts across the network, there should be no (LISTEN) flags and asterisks on the same line.
The last line of output shown, means that exim3 is listening for SMTP connections from the host called “debian” only. That's my local machine, and thus presents no problem.
But the third line has an asterisk, and then the www port (80) and the LISTEN flag. This means that anyone can connect to that port from the Internet. Unless you have good reason to be providing such services, there should be no socket listening for traffic from the wild on your machine.