dns_fping: a "conn" test with reverse nslookup

Hello all,

If you want to add an reverse DNS lookup to your "conn" test:

- You use CNAMEs for your devices and you want to see their real names
- You would like to see if your DNS reverse pointers are set correctly

Just use "dns_ping" !? (this is a simple wrapper around fping with awk)

https://github.com/bonomani/dns_fping/

Let me know if you found some optimisation, problem or if you like it.
Bonomani