I would like to ping a IP-Adress an want to be notified.
System: Linux Fedora.
Has anybody a idea or a Software?
Use this shell script. Found on http://jeromejaglale.com/doc/unix/shell_scripts/ping
#! /bin/sh
# -q quiet
# -c nb of pings to perform
ping -q -c5 google.com > /dev/null
if [ $? -eq 0 ]; then
echo "ok"
fi
Put the ping in a loop or run the script with cron.
Instead of echoing you can send a notification.
Related
So we have Embedded Linux board running Linux.
We can connect to that board using telnet and that spawns shell and gives access to it.
Now I am writing a bash script where I want to run commands on that shell and get its output.
e.g. My commands are something like below command over telnet and see if that was successful or not.
test -c /dev/null
When I run it like below I always get 1 as exit status
{ test -c /dev/null; sleep 1;} | telnet <board ip addr>
If possible I don't want to use expect,
Any suggestion/pointers ?
With SSH could trivially and robustly have done:
ssh yourhost 'test -c /dev/null'
With a simple shell on a TCP port, you could somewhat robustly but annoyingly have used:
echo 'test -c /dev/null; echo $?' | nc -q 1 yourhost 1234
telnet is instead notoriously timing sensitive and tricky to script, so since you don't want to do it robustly with expect, you can try to kludge it:
{ sleep 1; echo 'test -c /dev/null; echo $?'; sleep 1; } | telnet somehost
I have a requirement where I need to test is ssh tunnel is alive or not from different server.
This is how code looks like to check if the connection is live, if it is alive, it would send email.
#!/bin/bash
SERVERIP=192.xxx.xxx.xxx
NOTIFYEMAIL=xyz#gmail.com
SENDEREMAIL=alert#localhost
SERVER=http://127.0.0.1/
ping -c 3 $SERVERIP > /dev/null 2>&1
if [ $? -eq 0 ]
then
# Use your favorite mailer here:
mailx -s "Server $SERVERIP is down" -r "$SENDEREMAIL" -t "$NOTIFYEMAIL" </dev/null
fi
However, on running this ssh file, the below error is generated. can someone help me out.
No recipients specified
"/home/user name/dead.letter" 10/303
the -t switch force you to have a specific header format. Remove it and it will works better
The following code suppose to print "connected" repeatedly if ssh is able to connect to the remote machine, else "not-connected" will be printed.
#!/bin/bash
while [ "1" ]
do
ifconfig usb0 &>/dev/null
if [ "$(echo $?)" == "0" ]
then
sshpass -p passwd ssh -o ConnectTimeout=5 duser#10.1.1.3 sudo echo "connected"
else
echo "not-connected"
fi
sleep 0.2
done
The remote machine is connected via the usb0 interface. I am testing this script by frequently unplugging and plugging the usb interface. The problem is sometimes when i unplug the usb interfaces, the code stuck at ssh and it is not printing repeatedly. I suppose if ssh is interrupted in the middle of executing it is getting stuck. How can i overcome this ? Can someone help?
Most apparently its not hanging at all.
But the way you are printing connected seems like wrong.
This looks pretty much suspicious
sshpass -p passwd ssh -o ConnectTimeout=5 duser#10.1.1.3 sudo grep "connected"
What are you trying to grep ?
Normally if you need to grep the output of some app you need to do it via pipe e.g.
ls | grep "connected"
Since you are using bash, this is a much better way to do your test:
2>/dev/null >/dev/tcp/<ip_addr>/<port> && echo pass || echo fail
For more details, see the Bash documentation on redirections.
I am a beginner user of linux, and also quite newbie at ssh and tunnels.
Anyway, my goal is to maintain a ssh tunnel open in background.
In order to do that, I wrote the following batch that I then added into crontab (the batch is automatically processed every 5 minutes during workdays and from 8am to 9pm).
I read in some other thread in stackoverflow that one should use autossh that will ensure the ssh will always be ok through a recurrent check. So did I....
#!/bin/bash
LOGFILE="/root/Tunnel/logBatchRestart.log"
NOW="$(date +%d/%m/%Y' - '%H:%M)" # date & time of log
if ! ps ax | grep ssh | grep tunnelToto &> /dev/null
then
echo "[$NOW] ssh tunnel not running : restarting it" >> $LOGFILE
autossh -f -N -L pppp:tunnelToto:nnnnn nom-prenom#193.xxx.yyy.zzz -p qqqq
if ! ps ax | grep ssh | grep toto &> /dev/null
then
echo "[$NOW] failed starting tunnel" >> $LOGFILE
else
echo "[$NOW] restart successfull" >> $LOGFILE
fi
fi
My problem is that sometimes the tunnel stops working, although every thing looks ok (ps ax | grep ssh > the result shows the two expected tasks : autossh main task and the ssh tunnel itself). I actually know about the problem cause the tunnel is used by a third party software that triggers an error as soon as the tunnel is no more responding.
SO I am wondering how I should improve my batch in order It will be able to check the tunnel and restart it if it happens to be dead. I saw some ideas in there, but it was concluded by the "autossh" hint... which I already use. Thus, I am out of ideas... If any of you have, I'd gladly have a look at them!
Thanks for taking interest in my question, and for your (maybe) suggestions!
Instead of checking the ssh process with ps you can do the following trick
create script, that does the following and add it to your crontab via crontab -e
#!/bin/sh
REMOTEUSER=username
REMOTEHOST=remotehost
SSH_REMOTEPORT=22
SSH_LOCALPORT=10022
TUNNEL_REMOTEPORT=8080
TUNNEL_LOCALPORT=8080
createTunnel() {
/usr/bin/ssh -f -N -L$SSH_LOCALPORT:$REMOTEHOST:SSH_REMOTEPORT -L$TUNNEL_LOCALPORT:$REMOTEHOST:TUNNEL_REMOTEPORT $REMOTEUSER#$REMOTEHOST
if [[ $? -eq 0 ]]; then
echo Tunnel to $REMOTEHOST created successfully
else
echo An error occurred creating a tunnel to $REMOTEHOST RC was $?
fi
}
## Run the 'ls' command remotely. If it returns non-zero, then create a new connection
/usr/bin/ssh -p $SSH_LOCALPORT $REMOTEUSER#localhost ls >/dev/null 2>&1
if [[ $? -ne 0 ]]; then
echo Creating new tunnel connection
createTunnel
fi
In fact, this script will open two ports
port 22 which will be used to check if the tunnel is still alive
port 8080 which is the port you might want to use
Please check and send me further questions via comments
(I add this as an answer since there is not enough room for it un a comment)
Ok, I managed to make the batch run to launch the ssh tunnel (I had to specify my hostname instead of localhost in order it could be triggered) :
#!/bin/bash
LOGFILE="/root/Tunnel/logBatchRedemarrage.log"
NOW="$(date +%d/%m/%Y' - '%H:%M)" # date et heure du log
REMOTEUSER=username
REMOTEHOST=remoteHost
SSH_REMOTEPORT=22
SSH_LOCALPORT=10022
TUNNEL_REMOTEPORT=12081
TUNNEL_SPECIFIC_REMOTE_PORT=22223
TUNNEL_LOCALPORT=8082
createTunnel() {
/usr/bin/ssh -f -N -L$SSH_LOCALPORT:$REMOTEHOST:$SSH_REMOTEPORT -L$TUNNEL_LOCALPORT:$REMOTEHOST:$TUNNEL_REMOTEPORT $REMOTEUSER#193.abc.def.ghi -p $TUNNEL_SPECIFIC_REMOTE_PORT
if [[ $? -eq 0 ]]; then
echo [$NOW] Tunnel to $REMOTEHOST created successfully >> $LOGFILE
else
echo [$NOW] An error occurred creating a tunnel to $REMOTEHOST RC was $? >> $LOGFILE
fi
}
## Run the 'ls' command remotely. If it returns non-zero, then create a new connection
/usr/bin/ssh -p $SSH_LOCALPORT $REMOTEUSER#193.abc.def.ghi ls >/dev/null 2>&1
if [[ $? -ne 0 ]]; then
echo [$NOW] Creating new tunnel connection >> $LOGFILE
createTunnel
fi
However, I got some immediate message (below) when the tunnel is running and when cron tries to lauch the batch again... sounds like it cannot listen to it. Also since I need some time to get a proof , I can't say yet it will successfully restart if the tunnel is out.
Here's the response to the second start of the batch.
bind: Address already in use channel_setup_fwd_listener: cannot listen
to port: 10022 bind: Address already in use
channel_setup_fwd_listener: cannot listen to port: 8082 Could not
request local forwarding.
Every night I go through the same process of checking failover systems for our T1's. I essentially go through the following process:
Start the failover process.
traceroute $server;
Once I see it's failed over, I verify that connections work by SSHing into a server.
ssh $server;
Then once I see it works, I take it off of failover.
So what I want to do is to continually run a traceroute until I get a certain result, then run a SSH command.
Put your list of successful messages in a file (omit the variable lines and fractions of the line, and use a ^ to identify the start of the line, as such:)
patterns.list:
^ 7 4.68.63.165
^ 8 4.68.17.133
^ 9 4.79.168.210
^10 216.239.48.108
^11 66.249.94.46
^12 72.14.204.99
Then a simple while loop:
while ! traceroute -n ${TARGET} | grep -f patterns.list
do
sleep 5 # 5 second delay between traceroutes, for niceness.
done
ssh ${DESTINATION}
Use traceroute -n to generate the output so you don't get an IP address that resolves one time, but and a name the next, resulting in a false positive.
I think you could be better off using ping command to verify server's accessability than traceroute.
It is easy to check for return status of ping command without using any grep at all:
if [ ping -c 4 -n -q 10.10.10.10 >/dev/null 2>& ]; then
echo "Server is ok"
else
echo "Server is down"
fi
If you want to do it continually in a loop, try this:
function check_ssh {
# do your ssh stuff here
echo "performing ssh test"
}
while : ; do
if [ ping -c 4 -n -q 10.10.10.10 >/dev/null 2>& ]; then
echo "Server is ok"
check_ssh
else
echo "Server is down"
fi
sleep 60
done