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

Results for_spf.eemsg4.mail.mil

Resolver

Location

TXT

Name	TTL	Value
_spf.eemsg4.mail.mil	1664	spf2.0/pra ip4:214.24.21.96/29 ip4:214.24.22.96/29 ip4:214.24.24.96/29 ip4:214.24.26.96/29 ip4:214.24.27.96/29 -all
_spf.eemsg4.mail.mil	1664	v=spf1 ip4:214.24.21.96/29 ip4:214.24.22.96/29 ip4:214.24.24.96/29 ip4:214.24.26.96/29 ip4:214.24.27.96/29 -all