@jvazquez-r7 - My concern is that if the metasploit user wants to use a target of example.google.com with a rhost of pentestgeek.com, whatever DNS server the metasploit machine is making will need to query the google DNS server to resolve the example.google.com. This means if you are conducting an external pen test and you use a local DNS server you are sending the query from your address range. I just think it is better to prevent any packets what so ever from the network or address range the metasploit machine is on to hit the target in any way. And I have no problem with you questioning this, it is all about a matter of opinion in this case.