Miscellaneous Knowledge

On my cPanel server, I noticed that users where being given the incorrect FQDN (Fully Qualified Domain Name, e.g example.com) for mail.root as the SSL address for the mail server. This is odd, since there is no where to actually configure the SSL host address. After a bit of poking around, it seems it sets the address based upon the address of your SSL cert. In my case, I was using a Wildcard SSL certificate from CACert (free SSL certificates). However, as the certificate was a wildcard certificate, it had no idea what the actual FQDN you wanted was! After purchasing a cheap RapidSSL cert for £10 and installing it, the SSL Host FQDN displayed correctly for users. Plus they won’t get any certificate warnings any more!

I run my own home mailserver for two reasons, because I enjoy setting up systems and because I can. However, having just 1 mailserver introduces some problems. While according to the RFCs, sending servers are to keep sending failed mail for some time, they often dont. Consequently, if my server goes offline, loss of internet, reboot etc, I often loose a lot of email.

The solution to this is to have a Secondary MX (Mail Exchanger). This is another email server that will also accept email for your domain and keep trying to forward it to your Primary MX, forever. So, when my server comes back up, the email gets sent and not lost.

For a while, i’ve been using DNS Made Easy for my Secondary DNS and MX (don’t forget a secondary DNS, otherwise they can’t find out about your Secondary MX if your Primary DNS is down!). It worked, but not very well and recently i’ve noticed that i’ve been loosing email. DNS Made Easy have no information about their service status either, you have to trust that it’s working.

So, after searching for a while, I came across RollerNet. They provide many serivces, Primary/Secondary DNS/MX etc. I got a free account with them and was amazed at their quality of service. Most importantly, they give detailed logs of your MX status, such as mail received, mail in queue and the option to force-initiate a transfer of mail to your Primary MX. On top of that, they have all the usual spam filtering using the major blacklists, so no false-positives. Unfortunately, their free account has a limit of 50 messages a day (and many spammers target the Secondary MXes) so i’m now exceeding my message limit. No harm done though, i’m really impressed by their quality of service and going to take out a proper subscription. Good job RollerNet!