Robert Schetterer´s post (Botnet-Angriffe mit rsyslog und iptables recent module abwehren) to immediately add a IP by rsyslog to the firewall when they were rejected by postscreen has led me to present my solution here for syslog-ng. I do not use a pipe, but contribute about syslog-ng the appropriate IP […]
To prevent faked sender-adresses i recommend to use Sender Policy Framework (see www.openspf.org/Introduction). You can easily add the SPF-Modul from openspf.org to postfix. You need these three perl-modules Mail::SPF Net::DNS::Resolver::Programmable NetAddr::IP After installing the requied modules, get the SPF-modul from here. Extract the archiv and copy postfix-policyd-spf-perl to /usr/lib/postfix kopiert. […]
I use postscreen postscreen to prevent spam mails. Potential spam messages are rejected directly before they reach the server and the content must be scanned. You shouldn´t use postscreen if a Mail-User-Agents (MUAs) should be able to connect. Usually the TCP-Port 25 is only used for Mail-Transfer-Agents (MTAa) since MUAs […]