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

Results for_spf.mdp.comcast.net

Resolver

Location

TXT

Name	TTL	Value
_spf.mdp.comcast.net	7200	v=spf1 a:webmail.comcast.com ip4:96.114.127.0/27 ip4:68.87.28.32/27 ip4:96.103.94.0/26 ip4:96.106.48.128/26 ip6:2001:558:fe14:76:68:87:28:0/120 ip6:2001:558:fe21:39:96:114:127:0/120 ip6:2001:558:fd01:2b62::/64 ip6:2001:558:fd00:352c::/64 ~all