Open Port scaning for linux(Ubuntu)

If you want ever want to find the ports that are open in a target server or network you may use
utility call `nmap` .
eg :
 in Ubuntu       1. Install the nmpa using -- > sudo apt-get install nmap

                       2.port scan for target ip  -- >  nmap -v -sT 192.168.01.98

you may get an output like below . Please use `nmap `Manual page to find more options

Starting Nmap 5.21 ( http://nmap.org ) at 2012-10-17 18:45 PGT
Initiating Ping Scan at 18:45
Scanning 192.168.01.98 [2 ports]
Completed Ping Scan at 18:45, 0.01s elapsed (1 total hosts)
Initiating Parallel DNS resolution of 1 host. at 18:45
Completed Parallel DNS resolution of 1 host. at 18:45, 0.06s elapsed
Initiating Connect Scan at 18:45
Scanning 192.168.01.98 [1000 ports]
Discovered open port 80/tcp on 192.168.01.98
Discovered open port 8080/tcp on 192.168.01.98
Discovered open port 3306/tcp on 192.168.01.98
Discovered open port 445/tcp on 192.168.01.98
Discovered open port 22/tcp on 192.168.01.98
Discovered open port 21/tcp on 192.168.01.98
Discovered open port 139/tcp on 192.168.01.98
Discovered open port 8081/tcp on 192.168.01.98
Discovered open port 8090/tcp on 192.168.01.98
Completed Connect Scan at 18:45, 0.02s elapsed (1000 total ports)
Nmap scan report for 192.168.01.98
Host is up (0.00094s latency).
Not shown: 991 closed ports
PORT     STATE SERVICE
21/tcp   open  ftp
22/tcp   open  ssh
80/tcp   open  http
139/tcp  open  netbios-ssn
445/tcp  open  microsoft-ds
3306/tcp open  mysql
8080/tcp open  http-proxy
8081/tcp open  blackice-icecap
8090/tcp open  unknown

Read data files from: /usr/share/nmap
Nmap done: 1 IP address (1 host up) scanned in 0.13 seconds