How do I configure DKIM records?

Hi,

Here are some Linode Docs that will walk you through adding DKIM records to the Linode Manager:

https://www.linode.com/docs/networking/dns/dns-records-an-introduction/#dkim

https://linode.com/docs/email/postfix/configure-spf-and-dkim-in-postfix-on-debian-8/#set-up-dns

Per our guide on Creating a DKIM record, these records are implemented as TXT records.

A typical DKIM record will look like the following:

selector1._domainkey.example.com TXT k=rsa;p=J8eTBu224i086iK

Hi, sorry for a noob question but shell I replace the "example" with the domain name and leave the rest as in the example? Say my domain is supercool.eu so the record would look like so:

selector1._domainkey.supercool.eu TXT k=rsa;p=J8eTBu224i086iK

Thanks!

All "noob" questions are welcome :)

selector1._domainkey.supercool.eu TXT k=rsa;p=J8eTBu224i086iK

Yes, that should do it.

Though to clarify, when adding this to your DNS Manager, if you enter the below your domain (supercool.eu) will automatically be appended. So all you'd need to add in the Hostname and Value sections would be:

Hostname: selector1._domainkey
Value: k=rsa;p=J8eTBu224i086iK
TTL: default

One more question. Does this J8eTBu224i086iK remain same for all domains, like even for my domain it will remain same?

@tabarry --

You write:

One more question. Does this J8eTBu224i086iK remain same for all domains, like even for my domain it will remain same?

No, this is a crypto hash generated by your Linode. Mine is generated as follows:

opendkim-genkey -s $SELECTOR -d $DOMAIN -b $KEYLEN -D $DIR

where:

• KEY="mailkey"
• KEYLEN=1024
• SELECTOR=${KEY}.${KEYLEN}
• DOMAIN="mydomain.com"
• DIR=${HOME}/tmp   <<-- This dir has to exist. If it doesn't for you, use /tmp. This is where the file containing the hash you want to install ends up.

I update it monthly with a cron(1) job that invokes the Linode CLI.

opendkim-genkey is from the opendkim package -- see:

https://tecadmin.net/setup-dkim-with-postfix-on-ubuntu-debian/

for Debian/Ubuntu.

-- sw

Another noob q:
in the scenario of a cPanel instance, do you let it create the record for DKIM or use linode's DNS?
I'm getting the following and it doesn't seem right.

https://www.dropbox.com/s/2ybo8mlsznd8w4n/Screenshot%202024-01-02%20at%204.00.27%20PM.png?dl=0

I've never set up DNS records with cPanel personally, but based on the screenshot you shared, I found this post in Cpanel's support forum:

• cPanel Help - DNS Records

This explains that the error you're seeing is due to not using cPanel as the nameservers for your domain, and offers two solutions. It sounds like you have the option of using our DNS Manager or letting cPanel handle the records, but that either option requires certain steps that are further explained there.