Configure Destination

We differentiate between inbound and outbound directions for emails. Outbound refers to an email coming from you and going towards the internet. Inbound is the opposite direction, in which an email from the internet reaches you.

A destination is the host we send emails to if we receive it for one of your domains. Without a destination, we do not accept emails, even if you configured and verified a domain.

There are three main reasons why you would like to receive emails via p25.dev:

  • You sit behind a firewall and can't open port 25 inbound, but you can open other ports.
  • You would like to have a backup in case your own server goes offline.
  • You don't want to reveal your email server's identity, for example because it is linked to your IP address at home.

How to add a Destination

There are two ways to create a Destination:

  • While creating a Domain
  • On the "Destinations" page

Name field: A human-readable label. Helps you quickly identifying one of potentially many Destinations.

Host field: Accepts a hostname or IP address. This is how we will reach your host. We will not try an MX record, as this might lead to email loops.

It takes up to 5 minutes for your changes to take effect on our email servers.

Authentication

You can optionally switch on authentication and provide a username and password. You can use this option if you want to give your email server extra protection so that only p25.dev can reach it. You need a valid TLS certificate on your email server. We will try a STARTTLS connection. Without encryption, we will not send authentication credentials.

Modify and delete Destinations

You can modify Destinations at any time. This will affect all configured domains that are linked to your Destination.

You can only delete a Destination if it is not linked to any domain. This will prevent accidental deletions of active Destinations.

If you configured a domain, you need to add your destination to this domain, so p25.dev is able to route emails for your domain to your destination.

Go to Domains and configure your domain example.com to use your new destination "my-destination".

DNS configuration

For other email servers on the internet to know where to direct an email for you, they will look it up in DNS. There's one MX record you need to set: example.com 10 mx1.p25.dev.. You should not have more than one MX record configured for your domain, unless you know what you are doing.

The number 10 in this example refers to the priority that another email server chooses if there are multiple MX records defined. The lower the number, the higher the priority to try this host first.

mx1.p25.dev. is the hostname under which p25.dev accepts emails for your domain. This is a global name and not dependent on your account.

When starting with this configuration, set the TTL to 300. Once you are sure everything works as intended, you can increase the TTL.

Whenever you make changes to DNS records, it can take several hours for the changes to propagate.

Verify DNS

If you happen to have dig installed, you can verify that your MX record was properly added with dig MX example.com. You should see a response containing 10 mx1.p25.dev..

It can take a long time for this MX to show up in public DNS, up to a couple of hours.