I'm sitting at the Dana Street Roasting Company, which is kind enough to provide free wireless net access along with the coffee.
Since I'm not directly connected to my usual ISP (aci.net), they won't let me send mail through their SMTP servers. Since Erik had to batten down possible abuse of clock.org's SMTP servers, I can't send mail through there either.
Not to worry. I've been setting the "SMTP server" setting in Eudora to point directly to the destination of the message I'm sending out. Voila.
I often forget that just because a solution to a problem is obvious to me doesn't mean anyone else will think of it.