Office 365: How to verify a 1and1 domain
For 1and1 it appears that you first need to create a subdomain, then add the alias (in this case the address that you will be pointing to) from the subdomain.
For example, if I own the domain “mydomain.info” and then add it to O365 I will get instructions to create a CNAME record for ms85199829 (your exact string will be different, but it will contain “ms” plus 8 numbers).
O365 tells you to:
1) Go to your registrar and select the domain that you are verifying,
2) choose the option to add a CNAME record for your domain,
3) “In the CNAME or Alias box for the domain, type or paste ms85199829”.
4) In the Fully qualified domain name (FQDN) or Points to box, type or paste ps.microsoftonline.com.
For 1and1, the process is a little different. You will first need to create a subdomain, then create a CNAME for that subdomain, then add the alias, which in this case is actually the point to address.
For our example case you would:
1) Go to 1and1 and choose to admin mydomain.info,
2) Choose to add a subdomain, which will be ms85199829 so that you end up with the subdomain ms85199829.mydomain.info.
3) Click the box next to this newly created subdomain,
4) From the DNS menu, select Edit DNS Settings.
5) Click the radio button next to CNAME.
6) Next to alias, enter ps.microsoftonline.com (the point to address).
The CNAME record is actually an alias for another domain. The CNAME record just says use the pointed to domain instead whenever someone asks for this domain. This alias points to the canonical domain (the target domain to which we are pointing.
1and1’s process is probably more true to the actual definition to a CNAME record in that 1and 1 is adding a CNAME record to the ms85199829 subdomain that points to ps.microsoftonline.com. Most registrars have you add a CNAME or Alias to the parent domain (yourdomain.com) instead, and are actually “creating a subdomain for you” under the hood.