Check for missing reverse DNS entries on network

By justin, on May 26th, 2010

A quick way to check your network for IPs missing reverse DNS entries….

nmap -PE -sP 10.0.0.0/24 | awk '{if ($2 ~ /^[[:digit:]]/ ) print $2}'

http://blog.tonns.org/ Tony

What if your hostname starts with digit… say the serial # of the unit (-drac)?

I would say this is a little better:
nmap -PE -sP 10.0.0.0/24 | awk ‘{if ($2 ~ /^10.0.0/ ) print $2}’
but it gets more difficult the larger the subnet
http://blog.tonns.org/ Tony

What if your hostname starts with digit… say the serial # of the unit (-drac)?

I would say this is a little better:
nmap -PE -sP 10.0.0.0/24 | awk ‘{if ($2 ~ /^10.0.0/ ) print $2}’
but it gets more difficult the larger the subnet
justin

aha good point
justin

aha good point