How can I force the use of the smart host?

If you use scripts on your server, they can be abused by spammers to send messages directly over port 25 without being filtered by our outbound filter. Actually, there is no reason why a script should be able to send messages over port 25.

To prevent outgoing connections over port 25 and route all traffic through the EuropeanMX filter, you can use the following IP tables in your firewall:

IPv4

• Add

  ---

  iptables -A OUTPUT -p tcp --dport 25 -j DROP

• Remove

  ---

  iptables -D OUTPUT -p tcp --dport 25 -j DROP

  
  

IPv6

• Add

  ---

  ip6tables -A OUTPUT -p tcp --dport 25 -j DROP

• Remove

  ---

  ip6tables -D OUTPUT -p tcp --dport 25 -j DROP