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

Results forsmtp.spf.ziggo.nl

Resolver

Location

TXT

Name	TTL	Value
smtp.spf.ziggo.nl	3600	v=spf1 ip4:212.54.32.0/19 ip4:212.178.218.80/28 ip4:84.116.6.0/23 ip4:84.116.50.0/23 ip4:84.116.73.0/24 ip4:84.116.74.0/24 ip6:2001:731:8000:38::/64 ip6:2001:731:8000:34::/64 ~all