Para verificar que programa o aplicación esta usando un puerto TCP en particular, podemos utiliza el utilitario netstat.
netstat --help
usage: netstat [-veenNcCF] [] -r netstat {-V|--version|-h|--help}
netstat [-vnNcaeol] [ ...]
netstat { [-veenNac] -I[] | [-veenNac] -i | [-cnNe] -M | -s } [delay]
-t, --tcp
-p, --programs display PID/Program name for sockets
-a, --all, --listening display all sockets (default: connected)
-l, --listening display listening server sockets
[root@ENG04-SVR02 ~]# netstat -tapl
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
tcp 0 0 *:commplex-link *:* LISTEN 7187/iperf
tcp 0 0 *:rfe *:* LISTEN 8638/iperf
tcp 0 0 localhost:mysql *:* LISTEN 2024/mysqld
tcp 0 0 *:ndmp *:* LISTEN 2247/perl
tcp 0 0 *:http *:* LISTEN 2204/httpd
tcp 0 0 *:ssh *:* LISTEN 2080/sshd
tcp 0 0 localhost:smtp *:* LISTEN 2186/master
tcp 0 0 *:9050 *:* LISTEN 2218/php
tcp 0 0 *:https *:* LISTEN 2204/httpd
tcp 0 0 *:terabase *:* LISTEN 6258/iperf
tcp 0 0 10.117.51.164:ssh 10.10.106.125:37525 ESTABLISHED 6261/sshd
tcp 0 0 10.117.51.164:ssh 192.168.44.214:53198 ESTABLISHED 8505/sshd
tcp 0 0 10.117.51.164:ssh 10.10.106.134:59753 ESTABLISHED 28289/sshd
tcp 0 100 10.117.51.164:ssh 10.10.106.134:59739 ESTABLISHED 28071/sshd
tcp 0 0 10.117.51.164:ssh 10.10.106.125:37514 ESTABLISHED 6127/sshd
tcp 0 200 10.117.51.164:ssh 192.168.44.214:51089 ESTABLISHED 697/sshd
tcp 0 0 localhost:mysql localhost:48223 ESTABLISHED 2024/mysqld
tcp 0 0 localhost:48223 localhost:mysql ESTABLISHED 2047/rsyslogd