On the one hand, I mostly agree with Warner and John that it would be better for SF to be questions from professionals about managing computers.
On the other hand, apparently my instinct is to consider networking questions, even if they're badly phrased and from someone who's lost or clearly pertaining to a home network as "professional." Maybe I should quit answering things late at night...
Thinking about it now, both of those questions are probably bad, but you could have beginner questions that cover the same material, e.g. someone from a small company that used to outsource email and now wants to bring it in. That sort of beginner question should stay, but I think I'll go and cast the final close vote on that goofy private address space question.
EDIT: The message that shows up now that that question's been migrated sort-of confirms my feeling that SU isn't the right place for networking questions:
This question is related to computer hardware or computer software in general, and is a better fit for Super User