This application note shows the firewall configuration required to only permit a single PC on the LAN (192.168.1.10) to access SMTP mail server on the Internet. Other devices on the LAN will be blocked from accessing the SMTP server in the Internet. The example here uses the Vigor2760 but the same firewall configuration will apply to other DrayOS routers.
Go to Firewall >> Filter Setup configuration menu.
a) Select Filter Set 2 (Default Data Filter) and then select the next available filter rule to edit.
b) For direction select LAN/RT/VPN->WAN
c) For Source IP click on “Edit” and enter the IP address 192.168.1.10, then invert the selection.
d) Leave “Destination IP” as ANY
e) For Service Type: enter ports from ANY to 25
f) For Filter action, select “Block if No Further Match”