Re: [Exim] Re: stmp protocol violation, synchronization erro…

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Lähettäjä: Andrew - Supernews
Päiväys:  
Vastaanottaja: Mick Swisher, exim-users
Aihe: Re: [Exim] Re: stmp protocol violation, synchronization error, input sent without waiting for greeting
>>>>> "Mick" == Mick Swisher <mnswisher@???> writes:

Mick> Unfortunately we have a legitamate user attempting to send
Mick> inbound email from his dsl account and cannot get through.


Mick> 2004-03-15 01:02:57 SMTP protocol violation: synchronization error
Mick> (input sent without waiting for greeting): rejected connection from
Mick> H=adsl-66-141-211-211.dsl.tulsok.swbell.net [66.141.211.211]


What makes you think this is a legitimate user? That IP is listed on
DSBL, Spamcop and CBL (in addition to the expected DUL-type listings);
both the DSBL and CBL listings are less than 24 hours old. (Your logs
don't show a timezone, but if it's in -0600 as your message is, then
your log entry is only about 3 hours later than that time.) Judging
by the DSBL listing, the IP was at the time running a trojan-installed
proxy of the type commonly used by spammers.

Furthermore, if the actual owner of that IP at the time happened to be
your user (and is merely coincidentally infested with spammer trojans),
then the above log entry is _not_ likely to be the result of an attempt
by the user to legitimately send you mail.

The _only_ time you'll get legitimate mail rejected as a result of an
"input sent without waiting for greeting" error is this: if your
server is being notably slow producing the banner response (either due
to deliberate delays or because of slow response to rDNS or ident
lookups), and the sending mailserver is misconfigured with a stupid
timeout (the spec requires 5 minutes minimum; I've seen timeouts as
short as 5 seconds at uu.net and other badly-run sites).

--
Andrew, Supernews
http://www.supernews.com