How to find out what application is using your port

On Win XP i dont see 'l' option, is this some custom version of netstat.

On Win 2K3 the options are as follows (sorry, I don't have an XP system handy to see if they are the same): netstat -a -b -o -n

• -a: gets listening processes (similar to -l on linux)

• -b: displays the executable name that started using the port (similar to -p on linux)

• -o: displays the process id (PID) that owns the connection

• -n: (optional) gives the addresses numerically (same as -n on linux)

# lsof|grep 862 ypbind 1529 root 5u IPv4 4681 TCP *:862 (LISTEN)

The simplest method I've found is to do

$ sudo lsof -i :

where $ is your shell prompt.

for example

$ sudo lsof -i :22

COMMAND PID USER FD TYPE DEVICE SIZE NODE NAME

sshd 5143 root 3u IPv4 7777 TCP *:ssh (LISTEN)

A simple way i found to know whether the port is already used by any application.

type,

• telnet localhost <port-number>

If the telnet resides listening, then some process is using the port. Press ^] and then in the telnet terminal you can know the service name.

I want to find out which application is using a port on my XP machine. I tried using the netstat -aon command but it dosen't show the port in use. Is ther any other way to find out which application is using the port.

I have also tried telnet that too shows that the port is in use. Now can any1 help me tofind the application using the port.

I used netstat -na -o to list all active ports and their owner. Owner is lised as PID (process ID)