Matt wrote:
So is it a forgery if userA is on ISPB and wishes to send an e-mail
out as userA, even though ISPB blocks (as well they should) port 25?
Definately not!
It is if ISPB's smtp server which userA uses does not rewrite
the MAIL FROM to a domain which ISPB controls in the sense of SPF.
In this case ISPB acts just as a forwarder. What mechanism it uses
for the rewrite doesn't really matter, SRS is just one of them.
Please stop top posting! See http://www.google.co.nz/search?q=top+posting
Birger