Antispam, Best practices

Sending to Czech Republic? Have a look at the rules introduced by

Aleksandra Duło, 22 March 2021 (the word seznam means catalog) is a well known web portal and search engine in the Czech Republic, operating since 1996. The Czechs strongly believe in their own solutions and are faithful to them, therefore – attention! – in May 2012, Seznam was the second Internet search engine in the Czech Republic (42.84%) with Google in the first place (54.69%). Two years after the search engine’s launch, e-mails within domain were added to the Seznam portfolio . Currently, after a series of acquisitions, Seznam also owns the following domains:,,, and

Best Practices

For years, we have supported customers who, together with EmailLabs, send to dozens of European countries, including the Czech Republic. We know the guidelines behind from first-hand experience and we deepen this knowledge during transactional as well as marketing and newsletter performances. Moreover, we follow all changes made by the provider and have direct phone support at In order to enjoy satisfactory deliverability to this ISP you should comply with their recommended good practices; without them, our efforts to reach inboxes may fail.

With a significant share of Seznam users in your database, you cannot forget to:

  • send messages only to your own contact database, i.e. only to subscribers who gave their consents to receive emails;
  • regularly remove non-existent accounts and inactive users from your contact database;
  • always use the same from address;
  • send messages from a dedicated IP address;
  • avoid no-reply addresses (2way communication is recommended);
  • avoid sending from email addresses in free domains such as,, etc. Antispam filters will evaluate such messages much worse;
  • control the address used for sending and receiving messages (it should be fully functional and under control of the sender);
  • separate mailings into two different IP addresses (IP segmentation) and from addresses;
  • avoid capital letters, limit the use of emoticons and special characters in the subject of the message;
  • include a visible unsubscribe link in the body of the message.
Communication security also strongly focuses on the security of communication and sender authorization. There are signs that biggest trend in this area will be to strengthen senders using DMARC. At the moment, pays extra attention to the following issues:

  • SPF and dedicated DKIM are required (messages without a correct DKIM entry will be automatically marked as spam);
  • the domain in the address from and in the Return Path must exist and have MX records set.

If you are looking for a partner who will help you understand the above requirements, please feel free to contact us. At EmailLabs, we support an internal Black List that eliminates non-existent email addresses and potential spam traps from further mailings. We only use our own technology and dedicated IP addresses. We divide our smtp servers into transactional and marketing IPs and strongly support our clients in separating their traffic. Also we encourage users to avoid no-reply addresses – local inbox providers use simplified anti-spam mechanisms and this may be a signal to them that you don’t want to receive replies to your own email communication, which raises their suspicion of sending spam. We also offer help with configuration and collecting feedback loops (marked as spam).

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