[Info-vax] bizarre SMTP problem

[Phillip Helbig---remove CLOTHES to reply]

In article <49de854b$0$90270$14726298 at news.sunsite.dk>,
=?ISO-8859-1?Q?Arne_Vajh=F8j?= <arne at vajhoej.dk> writes: 

> I would consider it a bit rare for real email addresses.
> 
> But it is widely used for not quite real email addresss.
> 
> Read:
>  
> http://labnol.blogspot.com/2007/08/gmail-plus-smart-trick-to-find-block.html

Interesting.  That is actually the type of address which got me to start 
this thread.  Here is the gist:

   So any email address sent to billgates+microsoft at gmail.com or
   billgates+blog at gmail.com or billgates+website at gmail.com will still
   reach your billgates at gmail.com inbox though technically, they are
   three different email aliases.

   When you share your email with some non familiar service, like a
   newsletter, you can supply your existing email with a plus sign. If
   you ever receive spam addressed to that email alias, you know the
   exact source that's sending the spam and can easily block all emails
   using a GMail filter.

One can do something similar on VMS if one has privs.  Say I buy 
something online from some shop and they need an email address.  I give 
them shop at a.b.c, where shop is the name of the shop and a.b.c is my 
normal email domain.  Then, from a priviledged account:

   MAIL> SET FORWARD/USER=SHOP HELBIG

So I will get the email sent to shop at a.b.c along with my regular email, 
but a) can filter based on the To: address and b) since I gave this only 
to the shop, if anyone else uses it then either they got it from the 
shop or they guessed it.  The latter is unlikely if a) spam increases 
shortly after I set the address up (assuming I notice email sent to 
shop at a.b.c before that address actually does anything) and/or b I use 
something like shop_ejwiewjfiwjefijwoifjweio at a.b.c instead.  I can of 
course later remove the forwarding or direct it somewhere else.