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netstat script

Occasional Contributor

netstat script



Does anyone have a script which will do netstat into all servers listed on a file and create a list with server names and all established port details.


or in other way, a script to login to all servers and capture the o/p of 'netstat -avtn |grep -i established' in single file with server names


Thanks in advance


Patrick Wallek
Honored Contributor

Re: netstat script

Do you have SSH set up so that you can log into each server without providing a password?  If not, that is the first step.


If you do have SSH set up for passwordless logins, then something like this ought to get you started:





for SERV in $(< /dir/list-of-servers)


echo ${SERV}

ssh ${SERV} "netstat -avn |grep -i established"

echo ""

done > /dir/netstat-script.out



I remove the 't' option from your netstat command as that is not a valid option on HP-UX.


Your file with the list of servers in it should have one server name per line.


# cat list-of-servers


You will also need to modify the directory names and file names to suit you, but this should get you started.



Occasional Contributor

Re: netstat script



Thanks for the reply.. Issue is I dont have passowrdless ssh in place.  Also I dont have single password on all servers. i have around 3 different root passwords on different serevrs. So is there any way that I can put all these three password in one file and have the script to read that one by one.?



Patrick Wallek
Honored Contributor

Re: netstat script

Ahh...In this case you would have to use something like Expect to write your script.  You can have conditions in Expect so that should allow you to try different passwords.


I don't have any examples of an Expect script.  Perhaps some of the other folks here.

Dennis Handly
Acclaimed Contributor

Re: netstat script

>should have one server name per line.


Actually with $(< file), you don't need them one per line.

But if you ever want to switch to "while read server" you would.

Bill Hassell
Honored Contributor

Re: netstat script

When you don't have a single method to transfer files (ssh is very powerful for this purpose), I use batch ftp rather than Expect. Expect can be a challenge to install and use, whereas ftp can be controlled with a simple 'here document'  with the appropriate commands (including open, user and password).

Here's a simple example. Because these commands can be assigned to a variable, you can design your netstat gathering script to capture your data in a local file on each server and then transfer it to your central server on request or perhaps by cron. This is for a one time copy. Each run will overlay the previous run's file.


set -u
# Script to capture netstat/established data
# Customize with USER, PW for the collector system
# Local file is stored in the same location at the collector


DATESTAMP=$(date '+%Y-%m%d')
echo "$MYHOST - $DATESTAMP\n$(netstat -avn |
     grep -i established)" > $TEMPFILE

ftp -n -v $COLECTOR << EOF
  user $LOGIN $PW
  chmod 600 $TEMPFILE



By having the script run on each server, no login/password list is needed. And since netstat can be run by any user, there is much better security by creating an ordinary user to run the script on each system.



Bill Hassell, sysadmin