bin/176713: [patch] nc(1) closes network socket too soon

[Mark Delany]

> servers running certain protocols.  For example, the rules of the SMTP
> protocol... just to name one... require that a client wait until the
> server has sent out an initial greeting banner before the client sends
> anything to the server.  Some SMTP servers are lenient about enforcing
> this protocol rule, so in practice it may often not be necessary to wait

A while back "fast talkers" as they were called, were a known
signature of some spam bots. The guess is that they would just write
the whole SMTP transaction in one write() immediately following the
connect() and be done with it. A useful optimization when you're
blatting out billions of spam.

You don't see a big mention of this in search engines, so I don't know
how prevalent they are now.

Point being that such an option might be useful to avoid triggering
any detectors that might still be looking for this.


Mark.