To connect a subdomain when you didn’t connected the full domain. Yo need to do more DNS modifications.
But, don’t worry!
It is possible and not as hard as one can think.
For example, let’s connect subdomain.domain.com to OBR.
MX
| subdomain.domain.com. | 3600 | MX | 10 mail.subdomain.domain.com. |
CNAME
| www.subdomain.domain.com. | 3600 | CNAME | subdomain.domain.com. |
A
| mail.subdomain.domain.com. | 3600 | A | 67.222.25.128 |
| subdomain.domain.com. | 3600 | A | 67.222.25.128 |
SPF
| subdomain.domain.com. | 3600 | TXT | “v=spf1 a mx ip4:67.222.25.128 ~all” |
DMARC
| _dmarc.subdomain.domain.com. | 3600 | TXT | “v=DMARC1; p=none; rua=mailto:dmarc@dmarc.outboundrocks.com; ruf=mailto:dmarc-forensic@dmarc.outboundrocks.com; ri=86400; aspf=s; adkim=s; fo=1″ |