bind 9.2r8 and sendmail 8.11.0

[Bri-]

Hi,

When upgrading from bind 4.9.7 to 9.2r8 (pretty steep upgrade), one of the
the rules (5.1.8) kicks in and no longer permits me to email with an error;

501 Domain of sender address does not exsist

I'd rather not comment this rule out as bogus mail and spam are a pain.

Also, I will upgarde sendmail but it would be a good idea for me to know
what this error is a result of.
Any help?

Bri-