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I'm not sure you can support TLS (SSL) on multiple domains, at least not without running different postfix instances on unique IP:ports for each domain. Unless

by modoc 18y ago

I'm not sure you can support TLS (SSL) on multiple domains, at least not without running different postfix instances on unique IP:ports for each domain. Unless you're just using sub-domains and have a wildcard cert. It's the same issue you run into trying to host multiple SSL protected sites on the same IP. The server (Apache or Postfix) has to serve out the cert to encrypt the channel before reading the request data (which might contain the domain the client is connecting to). If you just want to have TLS setup on a primary domain, and also handle mail for other domains (without SSL protection), that's pretty easy.

izak30 18y ago
It was my understanding that the cert was for the domain of the server and not of the e-mail address. If I have this completely wrong, let me know.
- modoc 18y ago
  correct, the cert is for the domain, however in your CL posting you said you needed multiple domain virtual hosting. The cert is specific to a mail server hostname. It really depends on how you want the actual MX record and outgoing mail server setup. So if you're hosting three domains: domainone.com, domaintwo.com, and domainthree.com, you have a few options. You can set the MX of all three domains to mail.mymailserver.com, and have a single cert. However, that means all of your end users will have to point their IMAP/POP clients and outgoing SMTP server settings to mail.mymailserver.com, instead of mail.domainonce.com which might seem more logical to them. It also means that your outgoing mail headers will show the mail.mymailserver.com hostname, and you'll need to setup the right SPF records to avoid being flagged as spam due to domain mis-match. Or you can set the MX for each domain to mail.domainone.com, mail.domaintwo.com, etc... It really depends on your needs, and the needs of the client/users who are checking and sending mail, and how public you want the fact that all the domains are on the same server. Feel free to follow up with me via e-mail. devon@digitalsanctuary.com

by modoc 18y ago

izak30 18y ago

It was my understanding that the cert was for the domain of the server and not of the e-mail address. If I have this completely wrong, let me know.

modoc 18y ago
correct, the cert is for the domain, however in your CL posting you said you needed multiple domain virtual hosting. The cert is specific to a mail server hostname. It really depends on how you want the actual MX record and outgoing mail server setup. So if you're hosting three domains: domainone.com, domaintwo.com, and domainthree.com, you have a few options. You can set the MX of all three domains to mail.mymailserver.com, and have a single cert. However, that means all of your end users will have to point their IMAP/POP clients and outgoing SMTP server settings to mail.mymailserver.com, instead of mail.domainonce.com which might seem more logical to them. It also means that your outgoing mail headers will show the mail.mymailserver.com hostname, and you'll need to setup the right SPF records to avoid being flagged as spam due to domain mis-match. Or you can set the MX for each domain to mail.domainone.com, mail.domaintwo.com, etc... It really depends on your needs, and the needs of the client/users who are checking and sending mail, and how public you want the fact that all the domains are on the same server. Feel free to follow up with me via e-mail. devon@digitalsanctuary.com