rule       x
address    !
result     ""@

rule       x
address    a!
result     ""@a.MYDOMAIN

rule       x
address    !b
result     b@

rule       x
address    a!b
result     b@a.MYDOMAIN

rule       x
address    %
result     ""@

rule       x
address    a%
result     a@

rule       x
address    %b
result     ""@b.MYDOMAIN

rule       x
address    a%b
result     a@b.MYDOMAIN

rule       x
address    @
result     ""

rule       x
address    a@
result     a@

rule       x
address    a@.
result     a@.

rule       x
address    a@b
result     a@b.MYDOMAIN

rule       x
address    a@b.
result     a@b