Checking if a port is allready used

Outaspace has asked for the wisdom of the Perl Monks concerning the following question:

Replies are listed 'Best First'.
Re: Checking if a port is allready used by tirwhan (Abbot) on Jan 10, 2006 at 12:08 UTC
The `netstat` command will show you the status of your network connections `netstat -nat` Will print out a list of all open TCP connections with ports (on Linux, check your local manpage if you're running a different NIX, netstat tends to have subtly different syntax on the different variants). Since you're only communicating on the local host you'll likely only be interested in communications on 127.0.0.1 `netstat -nlt` will print out a list of sockets your machine is listening on (and which are therefore blocked). For Linux you can also add "-p" to give you the processes listening on these sockets (if you're root). BTW, if you're expecting to want to reuse the same port for a different process a lot, you should set SO_REUSEADDR when opening the socket for listening. Update:* Check out Net::Netstat::Wrapper for a Perl interface to netstat There are ten types of people: those that understand binary and those that don't.	[reply] [d/l] [select]
Re: Checking if a port is allready used by jbrugger (Parson) on Jan 10, 2006 at 12:08 UTC
Hi Outaspace, If you have a server, that has to be able to handle more connections simultaniously and asynchrone, i'd use something like an md5-hash to identify the client-server connecton (like a session-key). Anyway, your server-program has to decide if it's accepting more than one connection on a given port, since only one program at a time can listen on a given port. But since you don't provide mutch information about your design, used modules etc. i don't think a lot people can help you now. Perhaps you can have a look at cpan? Net::Server, IO::Socket, IO::Socket, Sockets: Client/Server Communication etc. "We all agree on the necessity of compromise. We just can't agree on when it's necessary to compromise." - Larry Wall.	[reply]
Re: Checking if a port is allready used by Limbic~Region (Chancellor) on Jan 10, 2006 at 13:38 UTC
Andre, It sounds like you want IO::Socket::PortState Cheers - L~R	[reply]
Re^2: Checking if a port is allready used by BrowserUk (Patriarch) on Jan 10, 2006 at 14:48 UTC
... which simply attempts to open the port and return true or false; but wraps that up in a complicated interface. Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error. Lingua non convalesco, consenesco et abolesco. -- Rule 1 has a caveat! -- Who broke the cabal? "Science is about questioning the status quo. Questioning authority". In the absence of evidence, opinion is indistinguishable from prejudice.	[reply] [d/l]