[Mimedefang] Sender validation

[Tony Nelson]

Quoting Daniel Taylor <dtaylor at vocalabs.com>:

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[snip]

> The SPF Milter allows you to define a default SPF record
> to be used when the site does not have a published record.
> 

I use the SPF Milter.. and missed the concept of default SPF record.  What would
make sense as a value?  mx ~all ?  What do you use, and how do you set it up?