On Fri, 24 Aug 2007, Guy Hulbert wrote:
> > fqdn + time + peer TCP port will be pretty unique, regardless of
>
> fqdn is the trivial part
>
> rand will be "pretty unique" ...
Initial connection time, peer IP, and peer port will only
repeat if the connection is torn down and restablished with
the same peer reusing the same local port within the resolution
of the timer.
The check_earlytalker plugin ensures at least a one
second pause in every SMTP session, so time() + peer IP
+ peer port will be far more unique than a random number :-)
This combo would be unique among all hosts attached to the same
routable networks -- two hosts on two different, unconnected
networks could possibly get a connection from the same
private IP + local port at the same time, but this "should
be impossible" if the networks are connected.
Adding this to plugins/logging/syslog works pretty well for
forkserver:
use Time::HiRes;
...
if (!$self->{_logid})
{
if ($self->connection->remote_ip)
{
$self->{_timestamp} = Time::HiRes::time();
$self->{_logid} = "t=" . $self->{_timestamp} . "/peer=" .
$self->connection->remote_ip . ":" . $self->connection->remote_port;
}
}
if ($self->connection->remote_ip)
{
$header = $self->{_logid} . " ";
}
syslog $priority, '%s%s', $header, join(' ', @log);
syslog messages look like this:
Aug 25 14:31:27 mailfoo qpsmtpd[4892]:
t=1188077487.69488/peer=10.1.253.1:40911 check_earlytalker
If there's an existing way to count the number of messages sent
during the connection, then append the count to _logid and it
becomes a message ID generator. If this isn't already somewhere
in SMTP.pm, the queueing plugin could increment a counter..
or the logging plugin could watch for the string 'to email address :' &
increment a (thread-safe) counter. That's a smidge brittle, tho..
a proper message counter would be less hacky.
James
