It can be anything! An apex, subdomain, or even a URL.

Results for_spf.reply.io

Resolver

Location

TXT

Name	TTL	Value
_spf.reply.io	300	v=spf1 ip4:104.42.42.126 ip4:104.42.43.41 ip4:104.42.198.122 ip4:104.42.53.248 ip4:104.42.195.62 ip4:104.42.199.12 ip4:104.42.43.137 ip4:104.42.194.90 ip4:52.246.115.13 ip4:20.190.132.0/22 -all