To add TXT records for DKIM to your Gandi hosted domain check out this helpful how-to video and follow the steps below.
Obtain the DKIM record from Postmark
Log into Postmark and navigate to the Sender Signatures section. Click Add a DKIM DNS Record or DNS Settings for the domain you are adding DKIM for.
You will then see entries for both DKIM and Return-Path:
These records will be used once you login to Gandi, so keep the DNS Settings window or tab open in your browser.
Adding the DKIM and Return-Path Records to Gandi
- Log in to Gandi, click on the Domains tab in the lefthand toolbar, and click on the domain in question.
- Click DNS Records tab.
- Click the Add to add a new record. We will start with adding the CNAME record.
- We will start by adding the CNAME record. For the Type, select CNAME from the drop-down.
- You can generally leave the TTL as it is.
- In the Name field, enter the Hostname value for the Return-Path record from the DNS Settings page in Postmark and in the Hostname field enter pm.mtasv.net. and then click Create.Note that you'll want to put a dot (.) at the end of the "pm.mtasv.net" value
- Click Add again to add another record for DKIM. For the Type, select TXT from the drop-down.
- In the Name field, enter the Hostname value you see for DKIM in your domain’s DNS Settings page in Postmark. It will be in the format of 2020040212345pm._domainkey. Then in the Text Value field, enter the TXT value for the DKIM record from your DNS Settings page in Postmark. Click Create.
- To finish verifying the CNAME and DKIM records, click on the Verify button in the Postmark DNS Settings page next to the DKIM and Return-Path records.
If everything is propagated (which can take up to 48 hours for new DNS records) and working, you will see a green checkmark in your Sender Signatures page showing that the domain has been verified. You can now also send from any email address on that domain.