this is a sample of port forwarding on linux.
1.add forwarding settings.
# sysctl -w net.ipv4.ip_forward=1 # echo "net.ipv4.ip_forward = 1" >> /etc/sysctl.conf
2.add forwarding parameter.
#iptables -t nat -A PREROUTING -m tcp -p tcp --dst WAITING_ADDR --dport WAITING_PORT -j DNAT --to-destination DET_ADDR:DEST_PORT #iptables -t nat -A POSTROUTING -m tcp -p tcp --dst DEST_ADDR --dport DEST_PORT -j SNAT --to-source WAITING_ADDR
This is sample shell script to loop between the date ±1 specified by argument.
#!/bin/sh
START=$1
END=$2
START_1DAY_BEFORE=`date '+%Y%m%d' -d "1 days ago ${START}"`
END_1DAY_AFTER=`date '+%Y%m%d' -d "-1 days ago ${END}"`
echo $START_1DAY_BEFORE
for j in {0..10000}; do
TARGET_YYYYMMDD=`date '+%Y%m%d' -d "-$j days ago ${START_1DAY_BEFORE}"`
echo ${TARGET_YYYYMMDD}
if [ ${TARGET_YYYYMMDD} -gt ${END_1DAY_AFTER} ]; then
break
fi
done
using command line to access web server.
openssl s_client -connect SERVER:443
If the web server is SNI, you can use the command as follows
openssl s_client -connect SERVER:443 -servername SNIName
1.sendmai forward setting.
sendmail.cf (sendmail.mc) , you can change SMART_HOST’s behaviof by using “[“.
[example] If you wanto to make sendmail forward always to mailserver.hoge.com, you should write the setting as follows.
DS[mailserver.hoge.com]
If you don’t use “[“, sendmail will decide the forward destination by searching MX record.
so It is no guarantee to forward mailserver.hoge.com.
2. stop forwarding except for specific domain.
(1)add alias
#echo 'trash: /dev/null' >> /etc/aliases #newaliases
(2)modify mailertable
#vi /etc/mail/mailertable hoge.jp.com smtp:[forwarding mail server] . local:trash (using "[ ]" to avoid searching MX record )
(3)convert mailertable
#makemap hash /etc/mail/mailertable < /etc/mail/mailertable
(4)resart sendmail
#/etc/rc.d/init.d/sendmail restart
3. If you could’t access DNS, and you want to forward another SMTP by sendmail.
make /etc/mail/service.switch. and write down as follows.
hosts files