XG310 (SFOS 16.05.5 MR-5) - MTA Mode - How do I restrict the WAN IP addresses used?

Question

How do I restrict the WAN IP addresses to receive and send e-mails? 
 I have 2 Wan connections with 5 IP addresses each. Of these, only one IP per WAN connection is to be used for sending and receiving mails. 
 So that for sending only addresses with valid PTR are used.

lferrara · Answer

MainAccount, 
 this is something not possible yet. Local Services are available to zones and not to Ip. I hope that this feature will be implemented very soon. 
 https://ideas.sophos.com/forums/330219-xg-firewall/suggestions/16593775-assign-the-built-in-services-vpns-admin-etc-to 
 Please vote the feature request. 
 For customers having multiple IP/ISP is a big big limitation. 
 Regards