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@thonixx

thonixx/reverse.sh

Last active Dec 21, 2015
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What would you like to do?
Do a reverse lookup easily
# ⣏⡉ ⡀⢀ ⣀⡀ ⡇ ⢀⣀ ⣀⡀ ⢀⣀ ⣰⡀ ⠄ ⢀⡀ ⣀⡀
# ⠧⠤ ⠜⠣ ⡧⠜ ⠣ ⠣⠼ ⠇⠸ ⠣⠼ ⠘⠤ ⠇ ⠣⠜ ⠇⠸
#
# Due to the complexity of parsing anothers output (and because everything
# is different on other linux versions) I decided to revamp the code.
#
# What's better:
# - multiple A record parsing (also with multiple PTR records now)
# - multiple PTR record parsing (now working w/o bugs)
# - better error handling based on empty result check
# - with the latest version many bugs are fixed now
#
#
# ⡷⣸ ⢀⡀ ⡀ ⢀ ⣰⡁ ⡀⢀ ⣀⡀ ⢀⣀ ⣰⡀ ⠄ ⢀⡀ ⣀⡀
# ⠇⠹ ⠣⠭ ⠱⠱⠃ ⢸ ⠣⠼ ⠇⠸ ⠣⠤ ⠘⠤ ⠇ ⠣⠜ ⠇⠸
# do a reverse lookup
# do a reverse lookup
reverse() {
# put request in variable
request="$1"
# check for request
if [ -z "$request" ]
then
echo "Please provide an IP or host name.".
return
fi
# check for "dig" installed
if [ -z "$(which dig)" ]
then
echo "Please install dig, we need it:"
echo "sudo apt-get install dig (for Ubuntu/Debian)"
return
fi
# decide if its an ip or name
if [ "$(echo $request | egrep -o '[[:digit:]]{1,3}\.[[:digit:]]{1,3}\.[[:digit:]]{1,3}\.[[:digit:]]{1,3}')" ]
then
# would be an IP
# for later check of any reverse
check="false"
# save/set IFS
oldifs=$IFS
IFS=$'\n'
# loop through ptr records
for r in $(dig +tcp +short -x $request 2> /dev/null)
do
# print ip address
echo -n "$request"
# print PTR
echo " > $r"
# set check to true due to at least one PTR
check="true"
done
# set the old IFS
export IFS=$oldifs
# check if any ptr was found
if [ $check == "false" ]
then
echo -ne "No reverse entry for $request.\n"
fi
else
# would be a hostname
# check if any output there
if [ -z "$(dig a +search +short +tcp $request 2> /dev/null | egrep -o '[[:digit:]]{1,3}\.[[:digit:]]{1,3}\.[[:digit:]]{1,3}\.[[:digit:]]{1,3}')" ]
then
echo "No A records found for $request."
return
else
# continue with a record(s)
# save/set IFS
oldifs=$IFS
IFS=$'\n'
# loop through A records
for i in $(dig a +search +short +tcp $request 2> /dev/null | egrep -o '[[:digit:]]{1,3}\.[[:digit:]]{1,3}\.[[:digit:]]{1,3}\.[[:digit:]]{1,3}')
do
# for later check of any reverse
check="false"
# loop through ptr records
for r in $(dig +tcp +short -x $i 2> /dev/null)
do
# print request and ip
echo -n "$request > $i"
# print PTR
echo " > $r"
# set check to true due to at least one PTR
check="true"
done
# check if any ptr was found
if [ $check == "false" ]
then
echo -ne "$request > $i > No reverse entry.\n"
fi
done
# set the old IFS
export IFS=$oldifs
fi
fi
}
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