Hinzufügen von TLS-Zertifikat zusammen mit SMTP-Konfiguration

Unterstützung Installation
1

Ich versuche, meinen eigenen nur zum Senden dienenden Server zum Versenden von E-Mails zu verwenden. Ich betreibe dieses SMTP-Gateway unter Verwendung von TLS, weshalb der Client, den ich zum Versenden von E-Mails verwende, ein Zertifikat benötigt. Ich verwende ein selbstsigniertes Zertifikat, das sehr einfach zu konfigurieren ist, wenn ich Postfix/ssmtp zum Versenden von E-Mails verwende, aber ich bin mir nicht sicher, wie ich ein benutzerdefiniertes Zertifikat im Discourse-E-Mail-Client verwenden kann.

Nur um sich kurz ein Bild zu machen:

Einfaches Szenario:
Discourse —sendet—E-Mail–\u003e Mailgun —sendet—E-Mail–\u003e Benutzer

Mein Szenario:
Discourse —sendet—E-Mail–\u003e mein Server mit SMTP-Gateway —leitet E-Mail über AWS SES-API weiter—\u003e Benutzer

Vielen Dank.

2

I would like to correct my question. So I really don’t need to add any certs for this to work but still its failing to communicate on TLS. If I am testing it with swaks its working fine. Example command:

swaks --to user@example.com --from me@example.com --auth PLAIN --auth-user myusername -tls -s smtp.somehost.com:2525
3

You can directly use the AWS SES SMTP to achieve this why do you want to have a local relay?

4

@itsbhanusharma AWS ses provides 60k emails per month free and as far as I know these email calls should be requested from ec2 instance to work otherwise they are charged as normal. My discourse instance is hosted on a digital ocean droplet. I could be wrong but this is my understanding and the reasoning behind it.

5

So even if Your SES API is receiving emails from a DigitalOcean IP, it would make it chargeable, You may decide to use another service or spin up exim on an ec2 instance to be a bridge between your DO droplet and AWS SES. I don’t think it’ll work but You can try.

It should (in theory anyway) be like:

  1. Discourse (on DO) sends emails to exim IP in EC2
  2. EC2 relays emails received from DO to SES
  3. SES delivers emails to the end user.
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6

I have already solved the relaying problem by running a local smtp server in ec2 which eventually forwards the smtp request to ses. The problem is discourse is failing on TLS handshake with this smtp server where as postfix/swaks and similar applications are working just fine.

7

Solving that should be as simple as using port 25 (without encryption)

8

Is there a way I can see where this SMTP handshake is handled? Like any library discourse is using in ruby behind the scenes? I don’t want to disable TLS here.

9

Then use a Valid SSL certificate (even letsencrypt should work fine)

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10

Using valid cert from letsencrypt didn’t help for some reason. Don’t know why.
But after setting this in app.yaml, emails are working now.

DISCOURSE_SMTP_OPENSSL_VERIFY_MODE: none

Someone with more knowledge about SMTP might provide why this is working but I am good for now I guess.

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11

Does this end up being cheaper than simply moving the discourse instance into S3?

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12

I have a $ 5 ec2 instance running on aws which I am using for relaying multiple domains. Moving discourse to ec2 would be a little costly from digital ocean, not much to be honest(few dollars over all).

But the point is even if I move discourse to ec2, I would still need that relay service to support rest of the droplets that I have on DO for other domains that I own. So why not just fix discourse :slight_smile:

13

Well, by your own admission Discourse isn’t broken, it interfaces with SES perfectly fine.

You’re doing this to circumvent an SES restriction to relay emails for free.

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14

That is true, but discourse has nothing to do with SES here. Discourse is communicating with a SMTP server, which could be anything(right now its a relay service). I was wondering how does postfix/swaks and all are working just fine with this SMTP server(from same DO vpc) and not discourse. After setting that var, it is working though. Still I would like to know what library we are using in discourse for SMTP handshake so that I can personally verify if there is anything we can do to improve in discourse.