Shell Programming and Scripting

Hi guys,

Im new on unix. but I need your help.
I have a windows program that is querying data from unix computer through winsock, this unix computer is bought from Japan in 1995. All the guys who are in charge of this have already resigned.
The problem is this winodws program is developed years ago i guess around 1995. this program is retrieving a data through this port 17477 from unix. But I didn't know what command should i throw to the listening port.

Code:

COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
prgsv 23208 root 3u inet 0x607e6cc8 0t0 TCP cen01:17477 (LISTEN)

Is there anyway that I will know what command the port is listening?

If your Unix server has the command: lsof then run it on the Unix server as the root user as follows:

Code:

# lsof -i

This will list all the processes listening on TCP/IP ports and on what port they are listening on, e.g. on my machine I have the SSH daemon running that listens on port 22 so I get:

Code:

$ sudo lsof -i
[sudo] password for user: 
COMMAND    PID        USER   FD   TYPE DEVICE SIZE/OFF NODE NAME
sshd      1741        root    3u  IPv4   6946      0t0  TCP *:ssh (LISTEN)
sshd      1741        root    4u  IPv6   6949      0t0  TCP *:ssh (LISTEN)
$ ps -ef | grep 1741 | grep -v grep
root      1741     1  0 Jan30 ?        00:00:00 /usr/sbin/sshd
$ grep ssh /etc/services
ssh		22/tcp				# SSH Remote Login Protocol
ssh		22/udp
$

I have removed the other lines lof output for clarity.

So in your case if port 17477 is not listed in /etc/services than lsof will just show the port number, note the PID (1741 in my case) and grep for that pid from the ps list and you then know what application is listening on that port.