Legitimate Mail Being Blocked¶
If you find that legitimate mail you send is being blocked, in many cases this is attributable to a lack of FCrDNS. Without this set up, a lot of remote mail servers will likely see mail sent from your server as spam.
Setting up FCrDNS in a standards-compliant way is fairly easy, with two main steps:
Give your server a hostname that resolves to an IP on the server
Configure your rDNS record for that IP to the same as the server hostname.
With a setup like this, the hostname resolves to the IP, and the IP points back to the hostname, giving your mails a basic air of legitimacy.
How you set your hostname varies from operating system to operating system, and relevant documentation should be used for each one.
Note
We recommend you set the hostname to something like mail.yourdomain.com. This is a fairly standards-compliant choice and it’s highly likely you already have a ‘mail.yourdomain.com’ record for your domain.
Reverse-DNS is a system which lets you define what hostname an IP address resolves to. Your server will have an IP address and, by default, will reverse-resolve to ip.ip.ip.ip.srvlist.ukfast.net. It’s important to set you hostname to something that does not contain an IP address, as the default does.
To configure it, log in to MyUKFast and go to the server in question, where you will see a page like this:
In the rDNS field, enter the hostname you chose earlier and press Update.
Your new hostname will be reflected instantly, but it will take time for the reverse-DNS to propagate across the internet - up to 48 hours - so give it time before checking everything is in place.
In a similar vein, it’s also recommended you set up an SPF record for your domain. This is covered in more in-depth in Configuring SPF Records
Further guidance¶
Please read our documentation on email blocklists as well as the basics of email to ensure you get everything set up properly to begin with.