Allow outgoing port 25 only from one IP in LAN

[Jacka]

Hello,

I want outgoing e-mails to be sent only by my mail server (local server, IP: 192.168.0.200) and to deny use of port 25 from other IP’s in my LAN. To avoid spam being sent from compromised PC’s.
What is best way to accomplish this ?

If someone could help me with the firewall rules I would really appreciate.

Thank you.

[janisk]

in firewall just set up rule that will check TCP protocol chain forward src-address=!192.168.0.200 action=drop

[Jacka]

@janisk

in firewall just set up rule that will check TCP protocol chain forward src-address=!192.168.0.200 action=drop

Not so easy.

If I add the rule below I can’t telnet mail.domain.com 25 from outside, the port is closed.

/ip firewall filter add action=drop chain=forward disabled=no dst-port=25 protocol=tcp src-address=!192.168.0.233

[efaden]

@Jacka

@janisk

in firewall just set up rule that will check TCP protocol chain forward src-address=!192.168.0.200 action=drop

Not so easy.

If I add the rule below I can’t telnet mail.domain.com 25 from outside, the port is closed.

/ip firewall filter add action=drop chain=forward disabled=no dst-port=25 protocol=tcp src-address=!192.168.0.233

Add out-interface=ether1-gateway.