Take the 2-minute tour ×

Wat happens if two applications try to listen to the same port?

share|improve this question
add comment

2 Answers

up vote 2 down vote accepted

The second one that binds to the port will get an error saying something else is already listening on the port.

share|improve this answer
Does the program check for itself if some other program is listening to the port? –  Wintermute Mar 3 '11 at 20:33
The operating system does the check. –  carson Mar 3 '11 at 20:41
add comment

Unless they are spawned via tcpmux, the first application binds to the port and listens for connections to it, while the second one cannot bind and cannot listen.

share|improve this answer
What is it that prevents the application from binding to the port? –  Wintermute Mar 3 '11 at 20:36
When your application makes the relevant system call to "grab" the port, the operating system will "inform" it (via a relevant error code) that it is already taken. –  adamo Mar 3 '11 at 21:17
add comment

Your Answer


