bash script to check telnet status

oscarenzo · 01-24-2012, 09:09 AM

Hello guys,

Before to looking for in the web, i arrive here for help:

Look i have 2 servers running any service, as can be apache, that is running on the port 80, i would like do an script for from the server B, can check the 80 port of the server A, if is running, do:

service httpd stop

If the server B is not listening on the port 80, will start the httpd service
service httpd start

i have this code now:

Code:

if telnet -c 65.254.46.206 80 </dev/null 2>&1 | grep -q Escape; then
  echo "Connected"
  service httpd stop
else
  echo "no connection"
  service httpd start
fi

when the server B is not working, working fine, but when is working, take more time, trying, before any minutes do the echo and stop the service, are there any trick or way for reduce the time, by example check by 2 seconds only, if on 2 seconds not respond, do the condition.

thank you very.

rodrifra · 01-24-2012, 09:31 AM

Use nmap to check port's status.

oscarenzo · 01-24-2012, 09:45 AM

for how? can you explain to me a bit more?

oscarenzo · 01-24-2012, 10:11 AM

Quote:

Originally Posted by rodrifra

Use nmap to check port's status.

i tested using nmap, but this tool check if the port is open but now if the service is runing :S

other advice?

Cedrik · 01-24-2012, 10:15 AM

You could use netcat if you have it

Code:

if nc -z -w2 65.254.46.206 80 2>/dev/null; then
  echo "Connected"
  service httpd stop
else
  echo "no connection"
  service httpd start
fi

edit: removed unwanted -c option that came from pasted IP from OP's post :/

Cedrik · 01-24-2012, 10:18 AM

Quote:

Originally Posted by oscarenzo

i tested using nmap, but this tool check if the port is open but now if the service is runing :S

other advice?

If the port is open that means a program/service listens to it

oscarenzo · 01-24-2012, 11:52 AM

Quote:

Originally Posted by Cedrik

If the port is open that means a program/service listens to it

yes sorry, i tested in my V and work okay, but the problem now is that my provider use virtuozzo and when i run my script appear errors ad:

operation not permitted.

i would like thta you can help me do this script using telnet, is possible?

the idea for this script is set a cron for run each 5 minutes, and test if the service if running on the other server, is not runing, start the same service on this server, as this script will run each 5 minutes, for avoid that start again the service, check if the service if runing, if is runing and the service in the other service still down, not should do nothing.

please help me

Cedrik · 01-24-2012, 01:32 PM

What operation is not permited ?

oscarenzo · 01-24-2012, 01:43 PM

Quote:

Originally Posted by Cedrik

What operation is not permited ?

use nmap :s

Cedrik · 01-24-2012, 01:45 PM

Do you have netcat installed ?

Code:

type nc