How to look for TCP ports that are open on another linux machine

I want to connect to db2 database running on another linux machine B.

Before that, I need to check whether my linux machine A is able  to see the available ports on the machine B.

This can be done by using the command:

nmap  <ip adress of machine A>

example :

[root@RHEL6 ~]# nmap 172.18.25.229

Starting Nmap 5.21 ( http://nmap.org ) at 2012-04-03 18:11 IST
Nmap scan report for 172.18.25.229
Host is up (0.0013s latency).
Not shown: 997 filtered ports
PORT      STATE  SERVICE
22/tcp    open   ssh
80/tcp    closed http
50000/tcp open   iiimsf
MAC Address: 00:0C:29:70:E8:3F (VMware)

Nmap done: 1 IP address (1 host up) scanned in 24.65 seconds