asyncRevDNS - Asynchronous Reverse DNS lookups

WARNING
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This can quickly slam your DNS server pretty hard (default simultaneous requests is 1000).
This works for me in environment I use, but could have issues.

Zachary Bischof 2012

HOW TO USE
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To run, direct a list of IPs to stdin of script.

E.g.
Using echo: `echo "123.45.67.89\n98.76.54.32" | python reverseDnsAsync.py`

Using cat: `cat ips.txt | python reverseDnsAsync.py`

In the latter case, the file 'ips.txt' is a file with a single IP address on each line.

After completing, the script will print out the IPs and hostnames for each IP address it found in the form of '<IP address>,<hostname>'.

Any IPs not printed could not be found (e.g. due to timeout, NXDomain, etc)

Required libraries (not normally installed): twisted, IPy