I have a couple Docker containers that use email as an alert system or just for info like completed jobs. The server I would like to host them on has, for whatever reason, blocked email ports and you have to pay extra to have them turned on.
It seems to me tho, that I should be able to port all email through Tailscale to a local or even remote email client. For instance, in the case of setting the parameters in the Docker compose, it would look something like this:
SITE_NAME: mycoolwebsite
DEFAULT_FROM_EMAIL: email address
EMAIL_HOST: smtp
EMAIL_HOST_USER: email address
EMAIL_HOST_PASSWORD: email password
EMAIL_PORT: 100.x.x.x:587
Then, configure the local email client to listen on 100.x.x.x:587.
Would this be doable, or is there a better way?
Yeah, this should work (assuming by email client you mean MTA).
Alternatively, you can set up Postfix to deliver mail over SSH to another MTA by defining a new service in master.cf that calls sendmail on the destination server. This postfix could run in a container as well or on the host, whatever is reachable.
Old NixOS configuration for that here, see the default_transport and masterConfig parts: https://git.dblsaiko.net/systems/tree/modules/sys2x/mail/relay.nix?h=ssh-mail
Alternatively, if you don’t have another mail server somewhere that you want to relay to, the simplest option is probably to just have Postfix deliver into a local mailbox and access that over IMAP (the imaps port should not be blocked, right? You can use a non-standard port though). Turn off non-local delivery though.
I already have sendmail on the server. Is there something special about Postfix? Just asking,I’ve never run Postfix and I’ve never had this experience before with a host. I guess they think that if they charge an extra 6 Euros to flip the switch, people wouldn’t use it for spam purposes. I’m bound and determined to figure out a workaround just because.
There isn’t really, you can probably use sendmail as well. Postfix is just the MTA I’m used to and know can do all of this.
From what I’ve heard about sendmail’s config file, I personally wouldn’t want to use it specifically though…