Hello Ajith Sir,
On Mon, Aug 03, 2020 at 08:03:50PM +0530, Ajith Kumar wrote:
I am just trying to set up various services on a digitaloceandroplet. At present a web server, Moodle LMS and Bigbluebutton video conferencing server are running. The site is at https://scischool.in/ , the objectives are mentioned there. Like to try a mail server , like postfix. Any help in that direction would be very useful.
Setting up mail servers are proving to be very challenging these days due to two reasons:
1. There are many parts (more on this later) 2. The mails from the server often get rejected as spam. This needs a bit of work.
There are two information that would be useful: 1. Are you setting up the mail server on the same droplet as moodle? 2. What do you intend to do with it?
Mail Server Components ---------------------- A mail server has several components. Postfix is just one. You will need to install and configure all of them. There are turnkey solutions available and they are described later.
1. Mail Transfer Agent (MTA): Postfix is an MTA. This is used to send out mails.
2. Mail signer: OpenDKIM is used to sign mails. Unsigned mails are just dropped by most receiving servers.
3. Mail Delivery Agent: Dovecot. This is used to receive mails. You don't need this if you just want to send out mails (like from moodle). You'll need it if you want to hand out user accounts and receive mails.
4. Spam filter: SpamAssasin or RSpamd
5. Web Client: Roundcube, Sogo etc. One of this is needed if you need to have webmail.
Turn-key solutions ------------------ Configuration of all these parts well is a bit of a challenge. Most of us prefer to use turnkey solutions. Some are:
1. Mail in a Box (https://mailinabox.email/). Mail in a box needs a VM of its own.
2. Mailu (https://mailu.io/1.7/). Can run in docker
3. Mailcow (https://mailcow.email/). Can run in docker
If none of these solutions are viable, there are deployment scripts (mostly ansible) that allow you to deploy them remotely and automatically.
Manual configuration is still possible, but is very involved. It can be used if none of the above are viable.
Server Reputation ----------------- None of these measures ensure that your mails wont be dropped by another server as spam. This needs more work.
1. Blacklisted IP and domains: You need to make sure that your IP address and domain are not blacklisted. It's possible to get them whitelisted.
2. Reverse DNS: You should set R-DNS for your server. Not very hard on Digital Ocean.
3. DKIM, SPF, DMARC: These are standards used to reassure other servers that your server is trustworthy.
Despite all these, they do get often dropped - especially by Google (gmail, gsuite) and Microsoft (hotmail, office365). It's just a game of patience - getting your mails marked as not spam by others.
These are the intial information I can offer you. Let us get to know your specific requirements and we can come up with some solution.
Regards, Gokul Das B