Qmail Support Forum

Anderson Miranda · Guest

Hi, I know this is an old discussion, but I've got a few questions about it.

First, I would like to know how good is to deny (5xx) the hosts that
tcpserver was unable to do a reverse lookup. Is out there many "good"
SMTP servers wich have no properly reverse DNS setted up?... I'm asking
this just because I'm afraid to keep denying "good" SMTP servers instead
of just spammers with poorly configured SMTP servers.

Actually, I'm just logging the bad reverse DNS requests to a separate
log file. My second question is how could I "flag" the messages whose
reverse DNS lookup failed?... Is that possible?...

Hope someone can help me with this thread.
Thanks in advance,
Anderson from Rio

PS: Below are all my related files to this question.

TcpRules File (/etc/tcprules.d/tcp.smtpd.cdb)
// ==========================================
127.0.0.1:allow,RBLSMTPD="",RELAYCLIENT="",MAXCONNIP="12",TARPITCOUNT="0",TARPITDELAY="3"
192.168.0.:allow,RBLSMTPD="",RELAYCLIENT="",MAXCONNIP="12",TARPITCOUNT="0",TARPITDELAY="3"
200.170.139.35:deny
200.174.142.161:deny
200.255.218.82:deny
8.4.112.100:allow,MAXCONNIP="5",TARPITCOUNT="10",TARPITDELAY="50"
=:allow,MAXCONNIP="2",TARPITCOUNT="10",TARPITDELAY="50"
:allow,MAXCONNIP="2",TARPITCOUNT="10",TARPITDELAY="50"
// ==========================================
The above file uses the "=" operator because I had an RBLSMTPD="-bad
reverse DNS" at the last line, but removed this to NOT deny the connections.
// ==========================================
#!/bin/sh
#BOF
#The "run" script for the supervisor of the qmail-smtpd:
QMAILDUID=`id -u vpopmail`
NOFILESGID=`id -g vpopmail`
MAXSMTPD=`cat /var/qmail/control/concurrencyincoming`
MAILSERVER=`cat /var/qmail/control/me`
exec tcpserver -l $MAILSERVER -t15 -r -h -p -v -c"$MAXSMTPD" -x
/etc/tcprules.d/tcp.smtpd.cdb \
-u"$QMAILDUID"
-g"$NOFILESGID" 0 smtp \
sh -c 'test -z
"$TCPREMOTEHOST" \
&& exec
/usr/bin/startsmtpd.sh bad "$MAILSERVER" \
|| exec
/usr/bin/startsmtpd.sh good "$MAILSERVER"' 2>&1
#EOF
// ==========================================
#!/bin/sh
#BOF
#The "/usr/bin/startsmtpd.sh" script, used to call qmail-smtpd and log
bad reverse DNS when needed:
rblsmtpd -b -c -r bl.spamcop.net /var/qmail/bin/qmail-smtpd "$2"
/home/vpopmail/bin/vchkpw /bin/true

XXX=`echo "$TCPREMOTEIP" | grep "192.168.0."`
if [[ "x$XXX" == "x" ]]; then {
if [[ "x$TCPREMOTEHOST" == "x" ]]; then {
TODAY=`date +"%d/%m/%Y - %A"`
NOW=`date +"%H:%M:%S"`
MYDATE="$TODAY $NOW"
echo "$MYDATE - 553 bad reverse DNS!" >>
/var/log/qmail/rblsmtpd/badreverse.log
echo "------Environment Vars:------" >>
/var/log/qmail/rblsmtpd/badreverse.log
echo "PROTO (TCP) = $PROTO" >>
/var/log/qmail/rblsmtpd/badreverse.log
echo "TCPLOCALHOST = $TCPLOCALHOST" >>
/var/log/qmail/rblsmtpd/badreverse.log
echo "TCPLOCALPORT = $TCPLOCALPORT" >>
/var/log/qmail/rblsmtpd/badreverse.log
echo "TCPREMOTEHOST = $TCPREMOTEHOST" >>
/var/log/qmail/rblsmtpd/badreverse.log
echo "TCPREMOTEINFO = $TCPREMOTEINFO" >>
/var/log/qmail/rblsmtpd/badreverse.log
echo "TCPREMOTEIP = $TCPREMOTEIP" >>
/var/log/qmail/rblsmtpd/badreverse.log
echo "TCPREMOTEPORT = $TCPREMOTEPORT" >>
/var/log/qmail/rblsmtpd/badreverse.log
echo "RELAYCLIENT = $RELAYCLIENT" >>
/var/log/qmail/rblsmtpd/badreverse.log
echo "-----------------------------" >>
/var/log/qmail/rblsmtpd/badreverse.log
} fi
} fi
#EOF

Maex · Guest

E.V.Devarajulu · Guest

Hi,

Could I know how to configure qmail to write a separare log file for bad
reverse DNS entries.

Thanks & Best Regards,

E.V.Devarajulu

Maex · Guest

jms1 · Joined: 19 Jul 2005 Posts: 1 Location: Orlando FL