Email Authentication configuration using SPF, DKIM and DMARC - what is the Selector value?

[elbeshti]

hi expert

kindly i need your help regarding the value of selector of DKIM as my configuration as below:

Ø  SPF Record

o   test.com   TXT     v=spf1 mx:esa1-test.com ip4:1.1.1.1 ~all

Ø  DKIM Record

o   selector1._domainkey.test.com        TXT     k=RSA; p=Public_Key

Ø  DMARC Record

o   _dmarc.test.com   TXT     v=DMARC1;p=none;sp=quarantine;pct=100;rua=mailto:reports@test.com

note that we had single domain : test.com

how i can determine the value and is this configuration ok or not

[Ken Stieers]

Look at the tools dmarcian.com or agari.com.

[joelbland · Accepted solution]

@elbeshti - the selector can be any value you choose. The selector allows a single domain to host multiple public keys.

[jorandre · Accepted solution]

Joelbland is correct in that you can use any value you want to. So, using "selector1" is perfectly valid. Some other options would be using a date like 11302018. That would be useful if you plan on replacing the key later down the road.

Other typical options used are to use part of your domain name like "test" and use a location like "boston."

The following is a link to the RFC that explain selectors in further detail: https://tools.ietf.org/html/rfc6376#section-3.1