Breaking issues with TCP connections

[novedevo]

• Needs error handling, not unreachable!() and unwrap()
• panics when port is not open at that IP
• infinite hang on, e.g., gmail.com and 1.1.1.1 literal
• haven't actually gotten a successful connection outta that port. Might be a residential internet problem?

[novedevo]

unreachable!(), for instance. is really just no mx record found, from what I can tell. This should be handled by reverting to the main DNS A/AAAA record, as per RFC.

[gennyble]

If no MX is found, the client now checks for an A record there. if no A or AAAA is found, we get to unreachable!() again. It's progress!