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Last update: 2021-10-15

Add a DKIM signature

You can add DKIM signatures to the headers of outbound emails by specifying the domain, a selector, and a private RSA key. A domain can have more than one signature.

To add a DKIM signature, do as follows:

  1. Go to Email > General settings. Scroll down to DKIM signing and click Add.
  2. For Domain, enter the FQDN of the domain.
  3. Enter the key selector.


    You can use the location or name of a specific mail server to identify outbound mails from the server, for example, London or mailserver1.

  4. Enter the private RSA key.


    You can generate the key, using a key generator, such as PuttyGen or Windows OpenSSL. A private key can have 1024 to 2048 bits. Don’t use RSA SHA-1.

  5. Click Save.

Update the TXT record for the DKIM signature on the DNS server. Once the DNS changes propagate, the DKIM signature will take effect.

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