Postfix SSL issue with multiple domains

I am hosting 2 domains on my Linode. does NOT have a SSL certificate, has a certificate installed.

I followed this guide … n-centos-7"> and successfully send emails using mutt.

Every is replaced with and hostname of my machine is (If I change it, /etc/resolv.conf gets reset and I start sending mails as, so I left that as it is.). However, this emails I sent are not encrypted and email clients, such as google, are complaining about it. Error did not encrypt this message.

/etc/postfix/ file contains:

smtpdusetls = yes

smtpdtlscertfile = /etc/pki/tls/certs/myotherdomaincom.crt

smtpdtlskey_file = /etc/pki/tls/certs/server.key

I got PositiveSSL certificate myotherdomain_com.crt from namecheap, when I registered a, server.key was generated when I issued

openssl req -new -newkey rsa:2048 -nodes -keyout server.key -out server.csr

The certificate is working when I use https on

When I send an email with mutt -f . command, while being in /home/vmail/ the email is send from and gmail complains that it isn't encrypted. If I use EMAIL="" mutt, gmail still complains that email isn't encrypted although in gmail, it appears that it came from, which is what I want.

I have a feeling that MTA uses with the certificate, while it should use it with

How can I resolve this issue?

1 Reply

This is what I do (which may not be what you want)

All my domains contain a MX record for their mail that points to (replace with one of your domains)

Run postfix on

Use a certificate for (I just re-used my webserver cert for server, but you should be able to use a letsencrypt cert for server)

All mail from all domains then originate from and the RDNS and certificates match and everyone is happy.

This work fine if you are not trying to hide that all you domains are related to the one server. I'm just a person, not a hoster, so it works for me and is simple to setup.


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