Introduction
DomainKeys Identified Mail (DKIM) DKIM or DomainKeys Identified Mail (DKIM) is a protocol that uses encryption to verify the sender of an email address. This protocol helps your recipients know that that the email is really coming from your servers, or servers you authorized to send on your behalf, and not from people pretending to be you. Enter the domain you'd like to generate keys for, for example dkimcore.org and hit the button. Security notes. This online wizard is fine for generating keys for testing and evaluation. If you decide to use DKIM Core in production, though, you might want to consider the security risks.
A selector is arbitrary string appended to the domain name, to help identify the DKIM public key. It is part of the DKIM signature, and is inserted into the DKIM-Signature header field. During the validation process, the selector adds an additional name component, allowing for differential DNS query names. A DKIM selector is text that is added with the domain to create a unique DNS record used during DKIM. This allows multiple keys to exist under one domain which allows for different signatures to be created by different systems, date ranges, or third party services. Knowledge base How to create a DKIM record with OpenSSL How to create a DKIM record with OpenSSL. The popular open source OpenSSL toolkit can be used to generate key pairs suitable for DKIM. DKIM keys are usually created by the service that sends email, such as Gmail, Mailgun, Mailchimp, etc.
This document describes how to configure DKIM signing on an ESA. Just dance 2017 steam key generator download.
Requirements
- Access to the Email Security Appliance (ESA).
- Access to DNS to add/remove TXT records.
Ensure that DKIM signing is off
Before we make any changes, we want to ensure that DKIM signing is off in all mail flow policies. This will allow us to configure DKIM signing without any impact to mail flow:
- Go to Mail Policies > Mail Flow Policies.
- Go to each mail flow policy and ensure that 'Domain Key/DKIM Signing' is set to 'Off.'
Create a DKIM signing key
You will first need to create a new DKIM signing key on the ESA:
- Go to Mail Policies > Signing Keys and select 'Add Key..'
- Name the DKIM key and either generate a new private key or paste in an existing one.
Note: In most cases, it's recommended that you choose a 2048 bits private key size.
- Commit the changes.
Generate a new DKIM signing profile and publish the DNS record to DNS
Next, you will need to create a new DKIM signing profile, generate a DKIM DNS record from that DKIM signing profile and publish that record to DNS:
- Go to Mail Policies > Signing Profiles and click 'Add Profile..'
- Give the profile a descriptive name in the field 'Profile Name.'
- Enter your domain in the field 'Domain Name.'
- Enter a new selector string into the field 'Selector.'
Note: The selector is an arbitrary string that is used to allow multiple DKIM DNS records for a given domain.
- Select the DKIM signing key created in the previous section in the field 'Signing Key.'
- Click Submit.
- From here, click 'Generate' in the column 'DNS Text Record' for the signing profile you just created and copy the DNS record that is generated. It should look similar to the following:
- Commit the changes.
- Submit the DKIM DNS TXT record in step 2 to DNS.
- Wait until the DKIM DNS TXT record has been fully propagated.
- Go to Mail Policies > Signing Profiles.
- Under the column 'Test Profile', click 'Test' for the new DKIM signing profile. If the test is successful, continue with this guide. If not, confirm that the DKIM DNS TXT record has been fully propagated.
Create Dkim
Turn DKIM signing on
Now that the ESA is configured to DKIM sign messages, we can turn DKIM signing on:
- Go to Mail Policies > Mail Flow Policies.
- Go to each mail flow policy that has the 'Connection Behavior' of 'Relay' and turn 'Domain Key/DKIM Signing' to 'On.'
Note: By default, the only mail flow policy with a 'Connection Behavior' of 'Relay' is the mail flow policy called 'Relayed.' The important thing to remember here is that we only want to DKIM sign messages that are outgoing.
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- Commit the changes.
Test mail flow to confirm DKIM passes
At this point, you are done with configuring DKIM any further. However, you should test DKIM signing to ensure that it's signing your outbound messages as expected and passing DKIM verification:
- Send a message through the ESA ensuring that it gets DKIM signed by the ESA and DKIM verified by another host.
- Once the message is received on the other end, check the headers of the message for the header 'Authentication-Results.' Look for the DKIM section of the header to confirm if it passed DKIM verification or not. The header should look similar to the following:
- Look for the header 'DKIM-Signature' and confirm that the correct selector and domain are being used: