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

Results forspf.mailcluster.com.au

Resolver

Location

NS

Name	TTL	Value
spf.mailcluster.com.au	86400	ns1.digitalpacific.com.au hostmaster.digitalpacific.com.au 2017121401 28800 7200 604800 86400

Name	TTL	Value
spf.mailcluster.com.au	900	v=spf1 ip4:101.0.120.32/28 ip4:103.250.20.0/28 ip4:202.130.44.224/28 ip4:202.130.45.0/28 ip4:116.90.4.32/27 ip4:116.90.5.32/27 ip4:116.90.2.128/27 ip4:116.90.5.64/27 ip6:2401:fc00:4:1::/64 ip6:2401:fc00:0:14::/64 ip6:2401:fc00:2:13f::/64 -all