netstat output

Shell Programming and Scripting
1

Hi Team,

Below is the output of netstat -an | grep 1533

tcp        0      0 17.18.18.12:583       10.3.2.0:1533           ESTABLISHED
tcp        0      0 17.18.18.12:370       10.3.2.0:1533           ESTABLISHED

Below is the o/p of netstat -a | grep server_name

tcp        0      0 local_server:53083 remote_server:virtual-places ESTABLISHED
tcp        0      0 local_server:39470 remote_server:virtual-places ESTABLISHED

Does port number also changes for "-an" and "-a" options?

If yes how to identify the link b/w
Alphabatic port name (virtual-places) and Numerical port name (1533)

2

Seems to me the second and third digits of the 5-digit ephimeral port number are being left out in the your netstat -an listing somehow, looks like a bug to me...

3

Ip iddresses were modified.
Please treat below as o/p of netstat -an

tcp        0      0 local_ip:583       remote_ip:1533           ESTABLISHED
tcp        0      0 local_ip:370       remote_ip:1533           ESTABLISHED
4

OK, so then there is no bug.. The difference with netstat -an is that host names are used and the former just ip-adresses. The port numbers stay the same..

5

From the RHEL netstat manual:

   --numeric , -n
       Show numerical addresses instead of trying to determine symbolic host, port or user names.

   --numeric-hosts
       shows numerical host addresses but does not affect the resolution of port or user names.

   --numeric-ports
       shows numerical port numbers but does not affect the resolution of host or user names.

   --numeric-users
       shows numerical user IDs but does not affect the resolution of host or port names.

So you man get your required result with --numeric-hosts