Sender ID, How to Disable a Failed Microsoft Initiative

Sender ID uses 'spf2' to identify the DNS TXT record, leading one to believe that Sender ID is version 2 of the SPF framework.  It is not.  This misnomer denotes a broken framework championed by Microsoft.  Precautions need to be taken to prevent Sender ID from misusing SPF records.

The simplest way to prevent interference with SPF records is to create a Sender ID DNS TXT record with an empty policy as shown below:

Sender ID validation will not misuse the SPF record if the above empty record exists in the domain's TXT field.  This effectively turns off Sender ID validation.

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