The "redirect" modifier (edit)
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.
