How to Check.....

[jamesbonf]

I want to know OPEN Ports on a Linux box. One way is to scan system using NMAP......

Is There any way.....i mean any inbuilt comand in linux to scan OPEN port

[jcliburn]

su -c "/bin/netstat -ptuna"

Stretch your terminal window to remove line wrap and you'll be able to see it more clearly.

[lazlow]

You can also do it from externally from: https://www.grc.com/x/ne.dll?bh0bkyd2

As long as you trust that site, I feel a little safer knowing what the outside world sees. Even if my box had been tampered with extensively, it shows what the outside world can see.

[jamesbonf]

using "netstat -ptuna" i am able to see all the connections connected to my system......tht pretty good but....is there any other command which gives same output as nmap

For example.......

22/tcp open ssh
23/tcp open telnet
25/tcp open smtp
80/tcp open http
82/tcp open xfer
110/tcp open pop3
111/tcp open rpcbind
139/tcp open netbios-ssn
143/tcp open imap
443/tcp open https
445/tcp open microsoft-ds
631/tcp open ipp
901/tcp open samba-swat
904/tcp open unknown
993/tcp open imaps
995/tcp open pop3s