[Mimedefang] Timeouts when filter-sender is employed

[Dirk the Daring]

Background:
	sendmail v8.13.4 on SPARC Solaris 8/117350-25
	MIMEDefang v2.52

   sendmail alone runs fine and delivers E-Mail

   If I use MIMEDefang without the -s parameter, everything continues to
work

   If I add the -s to the invocation of MIMEDefang, then for all E-Mail
handled by the MTA, I see error messages like this:

     Jun 15 17:16:34 host sm-mta[23303]: [ID 801593 mail.info]
     j5FLESWV023303: Milter: data, reject=451 4.3.2 Please try again later

   In mimedefang-filter, I have:

##########
sub filter_sender {
    my($sender, $hostip, $hostname, $helo) = @_;

    # Can't be "psicorps.org" unless it's one of our IP's.
    if ($helo =~ /(^|\.)psicorps\.org$/i) {
        if ($hostip ne "127.0.0.1" and $hostip ne "209.170.141.XXX" and
            $hostip ne "209.170.141.XXX" and $hostip ne "209.170.141.103") and
            $hostip ne "209.170.141.XXX" and $hostip ne "209.170.141.XXX") {
            syslog('info', "MIMEDefang rejected a connection where Host $hostip said HELO $helo");
            return(0, "Connection Rejected: $hostip is not authorized to use $helo for identification");
        }
    }
    return (1, "OK");
}
##########

   The rest of mimedefang-filter is pretty much stock as it shipped with
MD.

   I do have "delay_checks" enabled in sendmail.mc, if that makes any
difference.

   All internal hosts are listed in the access map with:

GreetPause:INTERNAL.HOST.IP.ADDR	0
Connect:INTERNAL.HOST.IP.ADDR		RELAY

   The MILTER line in sendmail.mc reads:

INPUT_MAIL_FILTER(`mimedefang', `S=unix:/var/spool/defang/MIMEDefang/mimedefang.sock, F=T, T=C:30m;S:30m;R:30m;E:30m')

   MIMEDefang and the Multiplexor are invoked like this (broken up for
readability):

	/opt/mimedefang/bin/mimedefang-multiplexor
 	 -U defang -i 60 -l -T -I 200 -S local4 -E -L 60 -Y Plex
	 -s /var/spool/defang/MIMEDefang/mimedefang-multiplexor.sock
	 -p /var/run/mimedefang-multiplexor.pid

	/opt/mimedefang/bin/mimedefang -U defang -b 200
	 -s -P /var/run/mimedefang.pid -T -S local3
	 -p /var/spool/defang/MIMEDefang/mimedefang.sock
	 -m /var/spool/defang/MIMEDefang/mimedefang-multiplexor.sock

   /var/spool/defang and the needed subdirs exist, owner defang:defang,
mode either 700 or 750. These are on a RAM disk, created with:

swap    -       /var/spool/defang       tmpfs   -       yes     size=128m,nosuid

   I can't fathom why adding filter_sender starts giving me timeouts.
Any help would be appreciated.

Dirk