lookup reverse ip

Reverse IP

Reverse lookup is needed for several uses. To check what is the reverse of an IP address, one can issue:

         dig -t PTR +short 99.123.204.41.in-addr.arpa.        

Easily reverse an IP

Using "awk", reversing an IP address can be done with

         $ echo "41.204.123.99" | awk -F "." '{for (i=NF;i>=1;i--) printf $i"."; print "in-addr.arpa."}'        

Or putting this in a simple SHELL script (i.e "flip-ip.sh"):

         #!/bin/bash         echo $1 | awk -F "." '{for (i=NF;i>=1;i--) printf $i"."; print "in-addr.arpa."}'        

and calling it:

         $ ./flip-ip.sh  41.204.123.99        

Used in one line with "dig":

         $ dig -t PTR +short $(flip-ip.sh  41.204.123.99)