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 4.2.2.3
BASEDNS => 4.2.2.3

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

msf auxiliary(compare_results) > set NAMES www.fbi.gov
NAMES => www.fbi.gov

msf auxiliary(compare_results) > run
[*] Comparing results between 4.2.2.3 and poisoned.server...
[*] Querying servers for www.fbi.gov...
[*] Analyzing results for 1 entries...
[*]   - www.fbi.gov A 64.86.183.120
[*]   - www.fbi.gov A 64.86.183.99
[*]   - www.fbi.gov CNAME a33.g.akamai.net
[*]   - www.fbi.gov CNAME fbi.edgesuite.net
[*]   www.fbi.gov A 1.3.3.7
[*] Auxiliary module execution completed