Author: Luke Smith <firstname.lastname@example.org>
Date: Mon, 22 Jun 2020 17:27:57 -0400
Merge pull request #29 from dhruvsharma78/master
Added instructions for setting up reverse DNS
1 file changed, 13 insertions(+), 2 deletions(-)
diff --git a/README.md b/README.md
@@ -49,10 +49,21 @@ actually works perfectly.
3. You need two little DNS records set on your domain registrar's site/DNS
server: (1) an **MX record** pointing to your own main domain/IP and (2) a
**CNAME record** for your `mail.` subdomain.
-4. `apt purge` all your previous (failed) attempts to install and configure a
+4. **A Reverse DNS entry for your site.** Go to your VPS settings and add an
+ entry for your IPV4 Reverse DNS that goes from your IP address to
+ `mail.<yourdomain.com>`. If you would like IPV6, you can do the same for
+ that. This has been tested on Vultr, and all decent VPS hosts will have
+ a section on their instance settings page to add a reverse DNS PTR entry.
+ You can use the 'Test Email Server' or ':smtp' tool on
+ [mxtoolbox](https://mxtoolbox.com/SuperTool.aspx) to test if you set up
+ a reverse DNS correctly. This step is not required for everyone, but some
+ big email services like gmail will stop emails coming from mail servers
+ with no/invalid rDNS lookups. This means your email will fail to even
+ make it to the receipients spam folder; it will never make it to them.
+5. `apt purge` all your previous (failed) attempts to install and configure a
mailserver. Get rid of _all_ your system settings for Postfix, Dovecot,
OpenDKIM and everything else. This script builds off of a fresh install.
-5. Some VPS providers block port 25 (used to send mail). You may need to
+6. Some VPS providers block port 25 (used to send mail). You may need to
request that this port be opened to send mail successfully. Although I have
never had to do this on a Vultr VPS, others have had this issue so if you
cannot send, contact your VPS provider.