How Does Spam Protection Work at NexoraHost

This guide explains how spam protection works for your email accounts and how to configure it in Plesk. With the integrated SpamAssassin, you can reliably filter out unwanted advertising, phishing attempts and harmful emails.

What protects against spam?

At NexoraHost we use SpamAssassin – a proven open-source spam filter that is directly integrated into Plesk. SpamAssassin analyzes every incoming email and rates it based on various criteria:

• Sender reputation and blacklists
• Typical spam characteristics in subject and text
• Suspicious links and attachments
• SPF, DKIM and DMARC verification

Activate spam protection in Plesk

1. Log in to Plesk
2. Click Mail on the left
3. Select the desired email address
4. Click the Spam Filter tab
5. Check the box Enable spam filter for this email address
6. Click OK

Adjust sensitivity

You can set how strictly the filter should work. The value is given in points – the more points, the more likely the email is spam:

• 5 points (default): Good balance – most spam is caught, few false positives
• 3-4 points: Stricter – catches more spam, but also more legitimate emails
• 6-7 points: Looser – fewer false positives, but more spam gets through

We recommend starting with the default value of 5 points and adjusting if needed.

What happens to spam emails?

You can choose what should happen to detected spam emails:

• Mark in subject: The email is delivered normally, the subject gets a [SPAM] prefix. Good for testing in the first days
• Move to spam folder: The email ends up in a separate spam folder. Recommended for most users
• Delete: Spam emails are deleted immediately. Only choose this if you're sure no important emails will be lost
• Reject: The email is not accepted at all. The sender receives an error message

Check spam folder

If you have spam emails moved to a separate folder, you can find them:

1. In webmail at https://webmail.yourdomain.com
2. A folder named Spam or Junk will appear there
3. Check this folder occasionally – rarely, important emails accidentally end up there

Block or allow senders

You can specifically block certain senders or mark them as trustworthy:

1. In Plesk, click the Blacklist or Whitelist tab
2. Add email addresses or entire domains:
   • Blacklist: Emails from these senders are always marked as spam
   • Whitelist: Emails from these senders are never marked as spam – regardless of content
3. Click OK

SPF, DKIM and DMARC – additional protection

These three techniques not only protect against incoming spam, but also prevent spammers from using your domain for fake emails. SpamAssassin checks these entries automatically. How to set them up is explained in our article on DNS records.

Server-wide spam protection

In addition to SpamAssassin, our mail server filters suspicious emails before delivery:

• Emails from known spam IPs are rejected
• Viruses and malware in attachments are blocked
• Forged sender addresses (spoofing) are detected

More guides on DNS records and email security can be found in the articles in the left navigation.

Related guides

• Set up webspace
• Change nameservers – domain won't connect
• DNS not working / propagation
• Set up SSL correctly
• SPF, DKIM & DMARC (email)
• Email with your domain
• Make website faster
• Domain & DNS hub

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