After seeing the SBC/ATT server for Austin get poisoned, serve up advertisements, and eventually get taken offline, I decided to add a module to compare DNS results between two servers. In the following example, the ".gov" TLD has been poisoned with the bailiwicked_domain Metasploit module:

msf > use auxiliary/spoof/dns/compare_results

msf auxiliary(compare_results) > set BASEDNS

msf auxiliary(compare_results) > set TARGDNS poisoned.server
TARDNS => poisoned.server

msf auxiliary(compare_results) > set NAMES

msf auxiliary(compare_results) > run
[*] Comparing results between and poisoned.server...
[*] Querying servers for
[*] Analyzing results for 1 entries...
[*]   - A
[*]   - A
[*]   - CNAME
[*]   - CNAME
[*] A
[*] Auxiliary module execution completed