Christopher Chan wrote: > The dest mta is most probably doing a blank sender address verify on > all emails. Although running a mail server on a dynamic ip is > discouraged and use of the ISP's relay box is encouraged, I doubt that > in this case that it will make any difference unless the dest mta has > the ISP's ip(s) whitelisted which I doubt every much. The solution is > to use a verifiable returnpath with bonus points for setting DS. well, he'll need to configure his script to specify a valid FROM address, is that what you mean? it might require configuring his local sendmail to masquerade all outbound mail as whatever 'real' domainname he uses for email, like, peterl at standingwave.org ...