how to check the open ports

[Azaru]

Dear all,

Is any one know how to check the open port in our system?

azaru

[Paul Sperry]

Well first check your /etc/services file.

For ports not listed there use lsof.

You cna also use netstat.

[Paul Sperry]

Well first check your /etc/services file.

For ports not listed there use lsof.

You can also use netstat.

[Paul Sperry]

by the way you can get lsof here:

http://hpux.cs.utah.edu/hppd/hpux/Sysadmin/lsof-4.78/

[Azaru]

Dea paul,

is there any other way other than lsof? Like to display the whole output(opened ports) in an single command.

[VK2COT · Accepted solution]

Hello,

Many ways to check it on the local server.
For example:

a) Run:

netstat -an

b) Install tools like nmap:

http://www.insecure.org/

c) Or even:

telnet localhost portnumber

There are many Shell and Perl script
that can automate task in c). I have
one that specifically opens SMTP port 25
but it can easily be modified for other
ports:

http://www.circlingcycle.com.au/Unix-sources/scan-subnet-smtp-servers.txt

Cheers,

VK2COT

[Laurent Menase]

ndd -get /dev/ip ip_udp_status
ndd -get /dev/ip ip_tcp_status

[DavidJ]

netstat -an will show all ports in use on your system.

[Sp4admin]

You can check the open ports in the /etc/services or you can check the ports that are established using the "netstat -a" command.

sp,

[Azaru]

thanks everyone

azaru