Slow SMTP response

I’ve searched the threads in this forum regarding this subject, and none of them seem to apply to my situation, so I’m starting this new thread.

I have turned off reverse DNS lookup for qmail using the -H and -l flags in the /service/smtp/run file. My entry looks like this:

exec /usr/bin/softlimit -m 512000000
/usr/bin/tcpserver -v -R -H -l $HOSTNAME -x $TCP_CDB -c “$MAXSMTPD”
-u “$QMAILDUID” -g “$NOFILESGID” 0 smtp
$RBLSMTPD $BLACKLIST $SMTPD $VCHKPW /bin/true 2>&1

However, my users occasionally still experience very slow connection times when trying to send email. Even if I ssh into the server and telnet localhost 25, it takes 4-5 seconds to establish the telnet connection, and another 10 seconds before the SMTP banner is displayed.

If I reboot the server connection times are instantaneous, but after a few hours connection times get slow again. It’s not consistently slow, but it does happen often enough that we’re getting support calls when outlook times out and reports an error.

Thanks,

Larry Hiscock
AngelicHost