Your own mail server, what to look out for?

If you want to make use of your own mail server and you have an internet connection from Previder, here are a few important points to consider.

Port 25 enabled

Port 25 is enabled by default. Previder's engineers perform regular checks. Does Previder see an open-relay? Then we will contact you so that you can adjust it yourself.

The purpose of the adjustment is to ensure that no direct connections can be made to your mail server from the Internet. In this way, Previder, together with you, limits the risks associated with an incorrect or poorly configured mail server. Spammers are constantly looking for a mail server to act as an open relay. These so-called open relays can cause Previder to be blacklisted. Besides the inconvenience caused by spam, blacklisting also risks depriving more customers of e-mail. For this reason, Previder carries out checks at a fixed frequency.

In order to still be able to send e-mail via a Previder connection and its own mail server, Previder provides its customers with access to a so-called relay server, the mx.previder.nl. This server will initially receive your e-mail and then deliver it to your mail server. This has a number of advantages for you, namely:

Your mail server only needs to accept SMTP connections from mx.previder.nl;

The server mx.previder.nl acts as a fallback server. So if your own mail server is temporarily offline, the relay server catches the e-mail for you. The retention period of the relay is set to five full calendar days;

For customers with a domain name hosted at Previder, use of the relay is free of charge.

Please note that limits are in force on our relay server. These limits are as follows:

50 addresses per e-mail message;

50 e-mail messages per connection;

200 connections per hour;

E-mail messages may be a maximum (gross) size of 20 MB. This equates to attachments of up to about 10-12 MB per message.

Configuration

To use the relay server, you need to make a change to the MX records for your domain. Make sure the first MX record refers to mx.previder.nl and the second MX record refers to your own mail server. You also need to inform our support department where the e-mail should be delivered. You can do this by sending an e-mail to support@previder.nl. The engineers can then configure the e-mail to be delivered to the correct mail server.

Domain name not registered with us?

You may of course purchase an internet connection from us, but your domain name is hosted by another party. It is of course possible to transfer your domain name to us, but if you do not wish to do so, please contact our sales department. They can tell you all about the possibilities and costs of this relay service.

Using an extra relay for our relay?

If you use an extra relay before our relay server, for example a mail filtering service such as MX-Relay or Barracuda, please indicate this to our support department. This is because the check our mail servers perform on SPF records causes errors when e-mail comes in via an extra relay. To prevent e-mail from being wrongly marked as spam or even deleted, we need to whitelist these servers from SPF control.