Ability mail server dkim

DKIM (DomainKeys Identified Mail) is a technique used to authenticate the sender of an email message. It involves adding a digital signature to the message header, which is verified by the recipient's mail server to ensure that the message has not been tampered with or spoofed.

Here's how DKIM works:

  1. The sender's mail server generates a private key and a corresponding public key.
  2. The private key is used to sign the email message with a digital signature.
  3. The digital signature is added to the message header.
  4. The recipient's mail server verifies the digital signature by using the public key to decrypt the signature.
  5. If the signature is valid, the recipient's mail server knows that the message has not been tampered with and that it came from the claimed sender.

To set up a DKIM mail server, you'll need to follow these steps:

  1. Generate a private key and a corresponding public key using a tool like OpenSSL.
  2. Configure your mail server to use the private key to sign outgoing email messages.
  3. Add the public key to your DNS records as a TXT record.
  4. Configure your mail server to look up the public key from the DNS records when verifying incoming email messages.

Here are some common DKIM mail server configurations:

Postfix

  1. Install the opendkim package on your Postfix server.
  2. Configure opendkim to use the private key and to sign outgoing email messages.
  3. Add the following lines to your Postfix configuration file (main.cf):
    milter_protocol = 2
milter_default_action = accept
  4. Restart Postfix to apply the changes.

Exim

  1. Install the exim-dkim package on your Exim server.
  2. Configure exim-dkim to use the private key and to sign outgoing email messages.
  3. Add the following lines to your Exim configuration file (exim.conf):
    dkim_selector = default
dkim_private_key = /path/to/private/key
dkim_canonicalization = relaxed/simple
  4. Restart Exim to apply the changes.

Sendmail

  1. Install the sendmail-dkim package on your Sendmail server.
  2. Configure sendmail-dkim to use the private key and to sign outgoing email messages.
  3. Add the following lines to your Sendmail configuration file (sendmail.cf):
    DkimSelector default
DkimPrivateKey /path/to/private/key
DkimCanonicalization relaxed/simple
  4. Restart Sendmail to apply the changes.

Microsoft Exchange

  1. Install the Microsoft Exchange DKIM feature on your Exchange server.
  2. Configure the feature to use the private key and to sign outgoing email messages.
  3. Add the following lines to your Exchange configuration file (web.config):
    <dkim>
<selector>default</selector>
<privateKey>/path/to/private/key</privateKey>
<canonicalization>relaxed/simple</canonicalization>
</dkim>
  4. Restart the Exchange service to apply the changes.

Remember to update your DNS records to include the public key as a TXT record. The format of the TXT record should be:

_kexample._domainkey IN TXT "v=DKIM1; k=rsa; p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQC..."

Replace _kexample with the selector you chose, and MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQC... with the public key.

Once you've set up DKIM on your mail server, you can test it by sending an email message to a recipient's email address and verifying that the message is signed with a valid DKIM signature.