Google Cloud Platform disallows sending via port 25 (ref : https://cloud.google.com/compute/docs/tutorials/sending-mail), given this constraint how can I setup mail-in-a-box?
Well, don’t use Google Cloud Platform, for starters.
(Two providers are recommended in the setup guide. I’d suggest one of those.)
There is a reason I need to stick with GCP. If anyone has any helpful guidance on hacks to make this work on HCP that would be appreciated.
There is a reason the box needs port 25…
I suppose if you really were determined to make this work, you could look at the suggestion Google makes for using Enterprise Mail Servers, where you would need to open a VPN session to a point where you would have a static facing IP that you could then forward back there. This probably would require some specific setting to ensure MiaB would only send traffic over the VPN link and not any other outbound route.
Honestly, seems an awful lots of trouble, and introducing single points of failure to make this work when there are many other freeish and cheap options.
Necro’ing a 5 year old post. Please don’t do this again.
While your helpful attitude is extremely appreciated, there is no reason to necro a 5 year old post.