Setting up a subdomain via CNAME - can't setup subdomains on record that has a CNAME record

[user01245]

We're trying to set up a subdomain to use with Campaign. We can't delegate the whole domain via nameserver, so we have to go the CNAME route. Adobe's instructions ask us to set up a CNAME record pointing testdomain.companyname.com to Adobe while ALSO setting up subdomains below that record pointing to Adobe via CNAME. According to our IT department, this is impossible in their DNS system. You can't have subdomains of a record that is itself a CNAME record. Only a zone record can have subdomains. 

Has anyone ever setup Campaign this way successfully?  If so, how did you get around this restriction? 

In the example below the CNAME record for 'testdomain.companyname.com.' is what we can't setup, due to it needing to be a zone record to setup the m1, t1, res1 and domainkey records below it.  

Name	Type	Value
t1.testdomain.companyname.com.	CNAME	t1.testdomain.companyname.com.cname.campaign.adobe.com.
m1.testdomain.companyname.com.	CNAME	m1.testdomain.companyname.com.cname.campaign.adobe.com.
res1.testdomain.companyname.com.	CNAME	res1.testdomain.companyname.com.cname.campaign.adobe.com.
testdomain.companyname.com.	CNAME	testdomain.companyname.com.cname.campaign.adobe.com.
companynamedhs._domainkey.testdomain.companyname.com.	CNAME	companynamedhs._domainkey.testdomain.companyname.com.cname.campaign.adobe.com.

[SatheeskannaK]

@user01245 I will look at it this way.

• A zone record (file) is the container holding all the DNS information for a domain.
• A CNAME record is one specific instruction within that zone file, used to create aliases between domain names.

Usually, you can find CNAME records inside zone files, working alongside other record types to ensure the internet knows where to send traffic for your domain. So what adobe saying is correct.

[user01245]

Yes, but Adobe is asking us to add a CNAME record for something that is a zone.

In my example, testdomain.companyname.com is a zone.  Adobe needs us to add a CNAME record for that, which is impossible if it's setup as a zone.  

I found this article that explains it better:
https://www.isc.org/blogs/cname-at-the-apex-of-a-zone/

"ISC BIND 9 will therefore not allow you to add a CNAME at the zone apex because this will create a broken zone and cause DNS resolution failures. The interpretation of the CNAME record (per the DNS protocol) makes it nonsensical to have a CNAME coexisting with any other records for that same name."

[SatheeskannaK · Accepted solution]

That's interesting. I would suggest setting up a call with Adobe support and your IT department to decide on the next steps.

[Sukrity_Wadhwa]

Hi @user01245,

Since there hasn’t been any recent activity on this thread and as suggested by @SatheeskannaK, this use case should be addressed with the help of Adobe Support, so, we’ll be closing this question for now.

If you have any related questions or updates to share, please don’t hesitate to request to reopen this one or start a new thread. We’d be happy to take another look.

Thanks!