Traceroute script to filter behind firewall servers

[RamkumarA]

Hi Experts,

I have a list of servers in a file and i need to run traceroute command against each node and if the output for any node comes like * * * (pasted below), then that node should be emailed as behind firewall server. The traceroute output for ordinary servers will not return * * * in the output and just want to filter out only the behind firewall servers using the * * * pattern.

(example)

Traceroute output for behind firewall server:-

shcscp18:/clocal $ traceroute cli002pait01.cldc.chrysler.com
traceroute: Warning: Multiple interfaces found; using 10.128.243.234 @ ce0:1
traceroute to cli002pait01.cldc.chrysler.com (53.229.96.121), 30 hops max, 40 byte packets
1 passdca1.v2818.tcom.chrysler.com (10.128.243.2) 1.071 ms 0.717 ms 0.720 ms
2 passdcc1.v2801.tcom.chrysler.com (10.128.254.129) 2.625 ms 0.551 ms 0.529 ms
3 pascldc1.v1124.tcom.chrysler.com (10.133.254.26) 0.945 ms 0.962 ms 0.811 ms
4 crscldlab-sdcu1.vl103.tcom.chrysler.com (53.231.214.22) 0.691 ms 0.679 ms 0.744 ms
5 crscldlab-oddu1.vl104.tcom.chrysler.com (53.231.212.65) 0.758 ms 0.727 ms 0.653 ms
6 fwclbgv1.is.chrysler.com (53.229.103.196) 1.130 ms 1.065 ms 1.050 ms
7 crscldlab-oddz1-vl476.tcom.chrysler.com (53.229.103.178) 1.527 ms 1.488 ms 1.628 ms
8 * * *
9 * * *
10 * * *
11 * * *
12 * * *
13 * * *
14 * * *
15 * * *
16 * * *
17 * * *
18 * * *
19 * * *
20 cli002pait01.cldc.chrysler.com (53.229.96.121) 1.795 ms * *

Please advise.


Currently i am using the below script which is extracting the traceroute output for all nodes and sending that file.

for node in `cat /tmp/test1.txt`
do
echo "Traceroute output for $node" >> /tmp/result1.txt
echo "***************************************************" >> /tmp/result1.txt
traceroute $node >> /tmp/result1.txt
done
mailx -s "Trace route results" myemailid < /tmp/result1.txt

Thanks,
Ramkumar A.

[James R. Ferguson · Accepted solution]

Hi:

Consider this:

# cat ./mytrace
#!/usr/bin/sh
while read HOST
do
traceroute ${HOST} 2>/dev/null |awk '/\* \* \*/ {exit 1}'
[ $? -eq 1 ] && echo "${HOST} is firewalled" || echo "${HOST}_OK"
done < file

...

The input "file" contains the hosts to examine --- one per line. You can easily change the 'echo' to a 'mailx' like:

...
[ $? -eq 1 ] && mailx -s "${HOST} is firewalled" myemailid

Regards!

...JRF...

[Steven E. Protter]

Shalom,

There is no real reliable way to be certain a system is firewalled.

The *** is possible from a temporary network outage.

Anyway.


while read -r node
do
traceroute $node >> /tmp/result1.txt
fw=$(grep "* * *" /tmp/result1.txt| wc -l)
if [ $fw -ge 1 ]
then
echo "Firewalled"
else
echo "Not firewalled"
fi


done < list_of_hosts



My example is not intended to be complete but to be a template.

SEP

[RamkumarA]

Hi Guys,

Thanks for your advise.

I tried the script given by James and it works perfectly..

Thanks,
Ramkumar A.