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

Results forspf2.grnet.gr

Resolver

Location

TXT

Name	TTL	Value
spf2.grnet.gr	60	v=spf1 ip4:194.177.210.169 ip6:2001:648:2ffc:200::169 ip4:62.217.124.94 ip6:2001:648:2ffc:106::94 ip4:83.212.9.5 ip6:2001:648:2340:4::5 ip4:62.217.93.4 ip6:2001:648:2ffa:93::4 ip4:62.217.69.69 ip6:2001:648:2ffa:e::69 ~all