nolisting / multiple mx

[zxfrank]

I tested with gmail, works great.

When the target has multiple MX and the 1st timeout (nolisting), there's no fallback and the result is timeout

[s32x]

Hmm, this is awesome info. I've noticed a large number of timeouts however I assumed it was due to slow servers. I never considered checking the other mx servers. I'll definitely be debugging this tonight and let you know what I find. Thanks so much!

[s32x]

I've updated the verifier 834eecc to attempt a connection to all MX servers simultaneously (since we need to respond within 30 seconds) - using the first valid connection established. I'm hoping this helps however if you continue to see timeouts it is likely an extremely slow server and due to herokus 30 second timeout, we can't let a handshake take longer than that.

[zxfrank]

You Are A Genius!!

[s32x]

I've done my best to re-add the no-listing concurrent connection stuff. As far as I know the go-routine leak should be fixed. If not I'll take care of it without removing the concurrent server connection stuff