Hostname has returned multiple SPF Records
The use of alternative DNS RR types that was formerly supported during the experimental phase of SPF was discontinued in 2014. SPF records must now only be published as a DNS TXT (type 16) Resource Record (RR) [RFC1035]. See RFC 7208 for further detail on this change.
According to RFC 7208 Section 3.1: During the period when SPF was in development, requirements for assigning a new DNS RR type were more stringent than they are today and support for the deployment of new DNS RR types was not deployed in DNS servers and provisioning systems. The end result was that developers of SPF discovered it was easier and more practical to follow the TXT RR type for SPF.
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