Please note , below tutorial is for Centos that does not support Cmake
if you use a other distro please check if Cmake is installed and skip to the SRS postfix install step
This is just a tutorial how to enable SRS for email rewrite to work properly when using Dkim and other email security
first install needed files
yum install -y cmake3 unzip curl nano
Then we going fix Cmake3 so it can work as Cmake as not all programs reconise the install of Cmake3
alternatives --install /usr/local/bin/cmake cmake /usr/bin/cmake3 20 \
--slave /usr/local/bin/ctest ctest /usr/bin/ctest3 \
--slave /usr/local/bin/cpack cpack /usr/bin/cpack3 \
--slave /usr/local/bin/ccmake ccmake /usr/bin/ccmake3 \
--family cmake
Lets continue the install of SRS postfix
mkdir -p /tmp/sr
cd /tmp/srs
curl -L -o master.zip https://github.com/roehling/postsrsd/archive/master.zip
unzip master.zip
cd postsrsd-master
make
make install
Edit the needed config file to get it working and to reroute the emails so it can be rewritten
nano /etc/postfix/main.cf
Add 4 new lines to the end of the file so it can start the rewrite
sender_canonical_maps = tcp:localhost:10001
sender_canonical_classes = envelope_sender
recipient_canonical_maps = tcp:localhost:10002
recipient_canonical_classes= envelope_recipient,header_recipient
Add the program as a service so it can start at boot, ignore warnings if you have them
systemctl enable postsrsd # to start it at boot
systemctl start postsrsd
systemctl restart postfix
if all done , check if it is running properly
systemctl status postsrsd
Thats all , congrats on installing SRS for email ,now your forwarded emails will pass SFP checks
Be sure to check out our MimeDefang guide to add anti abuse headers
