The SPF record for domain replace the current record. The macro-expanded domain is also substituted for the current-domain in those look-ups.
Examples:
In the following example, the client IP is 1.2.3.4 and the current-domain is example.com.
"v=spf1 redirect=example.com"
If example.com has no SPF record, that is an error; the result is unknown. Suppose example.com's SPF record was "v=spf1 a -all". Look up the A record for example.com. If it matches 1.2.3.4, return Pass. If there is no match, the exec fails to match, and the -all value is used.
O significado domínio e domínio atual não é muito claro aqui.
O que acontece se o exemplo1.com tiver sido consultado,
example1.com IN MX 0 mx.example1.com.
example1.com IN TXT "v=spf1 redirect=example2.com"
mx.example1.com IN A 1.1.1.1
example2.com IN MX 0 mx.example2.com.
example2.com IN TXT "v=spf1 mx -all"
mx.example2.com IN A 2.2.2.2
O resultado do spf deve ser 1.1.1.1 OU 2.2.2.2?
Quando você redirect para um domínio, o domínio redirecionado se torna o destino de todas as pesquisas de DNS subseqüentes, como as executadas por mx .
Veja RFC 7208 § 6.1 :
The <domain-spec> portion of the redirect section is expanded as per the macro rules in Section 7. Then check_host() is evaluated with the resulting string as the <domain>. The <ip> and <sender> arguments remain the same as in the current evaluation of check_host().
Tags email smtp domain-name-system spf