Frank S. Bernhardt wrote:
> I'm getting grief from Message Labs in that they are complaining that
> they are receiving a '554 SMTP synchronization error' when they do a
So they send their HELO/EHLO before getting your server's greeting.
There is a recent thread "SMTP protocol violation?" which covers this.
> 3) When they do a telnet to us on port 25 they complain about a 'long'
> delay and then the 554 message.
Most probably they block your ident lookup and send no reject packet
(tcp RST or icmp port-unreachable). So it's not your fault, but you
could surely lower your timeout (rfc1413_query_timeout) from the 30s
default (I have 2s).
