Add a DKIM signature (MTA mode)
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:
- Go to Email > General settings. Scroll down to DKIM signing and click Add.
- For Domain, enter the FQDN of the domain.
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Enter the key selector.
Tip
You can use the location or name of a specific mail server to identify outbound mails from the server, for example,
London
ormailserver1
. -
Enter the private RSA key.
Note
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.
Warning
If you use PuttyGen to generate a private key with 1024 bits, the firewall doesn't add it. You must generate the private key with 2048 bits if you're using PuttyGen.
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Click Save.
Update the TXT record for the DKIM signature on the DNS server. Once the DNS changes are applied, the DKIM signature will take effect.
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