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

[Ronald F. Guilmette]

In message <20130721041338.2121.qmail at f5-external.bushwire.net>, 
"Mark Delany" <n7w at delta.emu.st> wrote:

>> 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.

That is correct.

>The guess is that they would just write
>the whole SMTP transaction in one write() immediately following the
>connect() and be done with it.

Yes.

>A useful optimization when you're
>blatting out billions of spam.

I suppose so.

>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.

I'm sorry, but I am not following you.

Were you attempting to say that this would be a good thing or a bad thing?

(Personally, don't think it matters much one way or the other.  Blocking
"fast talkers" was never a terribly effective anti-spam technique.  It was
just "security through protocol pendantry", and was/is quite entirely
trivial for the spammers to work around.)


Regards,
rfg