Anti-spam FAQ
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What is anti-spam and why does a business need it?
Anti-spam is a filter that removes unwanted messages, phishing and e‑mails with viruses from incoming mail before they reach the mailboxes. It protects employees from fraud and saves their time. Čistý mail is a dedicated anti-spam service placed in front of your mail server – your own or Microsoft 365 – with the settings fully in your hands.
Do I need to install anything?
No. Mail for your domain is routed through our servers where it is filtered, and only clean messages are delivered to your mail server. Nothing needs to be installed on computers or the server.
Does Čistý mail also protect against phishing and viruses?
Yes. Besides anti-spam it includes anti-phishing and anti-virus. Fraudulent e‑mails are caught by SPF, DKIM and DMARC checks, lists of fraudulent links (SURBL) and content filters; attachments are scanned by an anti-virus with an up-to-date database and dangerous file types are blocked. See also our guide how to spot phishing.
How do I set it up?
After activation you change your domain's MX records to our servers at your DNS provider. We will send you the values. The change usually takes effect within a few hours.
Does Čistý mail work with Microsoft 365?
Yes. Čistý mail sits in front of mailboxes in Microsoft 365 and other cloud services as an extra layer of protection. After changing the MX records you only need to allow delivery from our servers in the destination service – we will help with the setup.
Can I keep my mail on my own server rather than in the cloud?
Yes, Čistý mail is ideal for that. It protects your own mail server in your office or data centre, so your e-mail stays in your hands. Messages only pass through our filter and are stored temporarily only when your server is down.
What happens when our mail server goes down?
Messages are kept with us and delivered as soon as your server is available again. No mail is lost.
Can I decide what counts as spam?
Yes. In the web admin you choose whether dangerous messages are only tagged or redirected to another address, and you can keep your own blacklist and whitelist. Detailed statistics and logs are available too.
Where is the data stored and what about the GDPR?
All of the service's infrastructure – servers and backups – is located in the European Union. The service meets all GDPR requirements; we process customers' mail as a data processor solely for filtering and delivery. See our privacy policy for details.
What counts towards the number of protected addresses?
All addresses in the domain including aliases.
How do I log in to the admin?
At admin.cistymail.cz. You receive the login details when the service is activated. For secure sign-in you can turn on two-factor authentication (MFA) with a code from an app such as Google or Microsoft Authenticator.
How do I check whether my domain has correct SPF, DKIM and DMARC?
Use our free domain test. It shows the state of the records and suggests improvements.
How can I try the service?
Fill in the free trial form. We will activate anti-spam for your domain for 30 days, free and with no obligation.