Anti-spam setup for Plesk

Here are the instructions on how to set up Bytemark’s managed anti-spam service for customers who use Plesk (see here instead if you maintain your DNS by hand).

Before you start, please note that this is a cheap but chargeable service! Our charges are detailed here

If you have clients who use your server for direct authenticated SMTP (i.e. they use your server for outbound email as well as incoming), you will currently need to arrange alternative means for them to send their email once you’ve locked your server down. Sorry, we don’t yet have a solution for this.

Configuring nospam for a Plesk domain

You can easily try out our anti-spam service for one or two domains. Our servers will receive your email, filter out the spam, and pass the remainder on to your Plesk server. However for the service to be fully effective you must make sure no email is delivered direct (“locking down” your server), and this will entail making all your domains on the server use the service, or none at all.

Here is how to re-route mail for a domain via our nospam servers:

1. Click the ‘Domains’ tab on the left
2. Select the domain you wish to work on
3. Select ‘DNS Settings’

You should now see a list of DNS records for your domain.

1. Click ‘Add Record’, and enter a new record as follows:
   • Record type: TXT
   • Domain name: mailroute.nospam
   • TXT record: mail.yourdomain.com (where yourdomain.com is the name of the domain on which you’re configuring the service)
2. Click ‘Add record’ and enter a new record as follows:
   • Record type: MX
   • Domain name: (leave this blank)
   • Mail exchanger: a.nospam.bytemark.co.uk
   • Priority: 5
3. Click ‘Add record’ and enter another new record as follows:
   • Record type: MX
   • Domain name: (leave this blank)
   • Mail exchanger: b.nospam.bytemark.co.uk
   • Priority: 10

Now scan over the list of records in front of you – you should remove any MX records which aren’t one of the records you’ve just added. Select the old MX records and click ‘Remove selected’ at the top. Confirm this, and you’re done.

You can repeat this process for any number of domains for which you want to try out the anti-spam service. However for long-term usage, you must complete this process and lock your server down.

Locking your server down

You need to tell Plesk that only Bytemark’s anti-spam servers are allowed to send email direct to your server. If you don’t do this, spammers will probably carry on sending email direct, bypassing our spam servers, and you won’t see any benefit. We don’t anticipate this happening unless our service becomes better known to spammers, but we can’t guarantee results until you’ve done it.

Locking your server down means that all your server’s domains must use our anti-spam service. It currently also means your clients cannot use your server for authenticated SMTP relaying any more.

With these caveats in mind, the process is simple, and reversible if you need to:

First you need to ensure the firewall module is installed (you can skip this step if you know that it is):

1. Go to the Server tab on the left, then to Updater
2. Click on the version of Plesk you have installed (the one with the green tick beside it)
3. Tick ‘Plesk firewall’ if there is a tickbox beside it, then scroll up and click Install. (If there is no checkbox, but a green tick instead, then Plesk firewall is installed already.)
4. Confirm you wish to install the firewall, enter your email address and wait for an emailed confirmation from Plesk that the installation was successful

Then you need to configure the firewall itself to reject connections properly:

1. Click on the Modules tab on the left, then on the Firewall module from the list on the right
2. Click Edit firewall configuration
3. Click SMTP (mail sending) server
4. Change the option presented from Allow from all to Allow from selected sources, deny from others
5. You should see an empty list appear;
   1. enter 89.16.184.144/28 then click Add
   2. enter 89.16.176.76 then click Add
   3. enter 89.16.176.77 then click Add
6. Click OK to save the SMTP server settings
7. Click Activate at the top of the page to enable these firewall settings

This should cause your server to stop accepting email unless it has come from Bytemark’s anti-spam servers.

You can undo this lock-down by changing the SMTP server settings back to Allow from all