begin Tuesday 27 January 2004 11:16, Alex van den Bogaerdt quote:
#2: if they end up looping, the same will happen when the forwarding user
himself sends a message to himself.
If the forwarding user sends a message to himself, he gets the
message unharmed, just like he would get any other message.
If a message bounces (for instance because the iser forwarded his
pobox address to his gmx.net box which happens to be full), the
following will happen:
1. alice(_at_)yahoo(_dot_)com sends to bob(_at_)pobox(_dot_)com
2. pobox rewrites this message as:
bob(_at_)pobox(_dot_)com => bob(_at_)gmx(_dot_)net
3. Gmx bounces it:
<>@gmx.net => bob(_at_)pobox(_dot_)com
4. pobox forwards it again, replacing original sender:
bob(_at_)pobox(_dot_)com -> bob(_at_)gmx(_dot_)net
...=> ad infinitum.
Now, pobox.com could implement special protections (such as "never
forward mails from postmaster"), but what would it do instead:
- silently drop the message ===> not good. neither Alice nor Bob will
be made aware of the problem
- locally deliver the message to bob(_at_)pobox(_dot_)com ===> not good. Bob is
not in the habit of checking his maildrop @pobox.com, as it is
normally forwarded to his gmx account. The bounce will just sit there
unnoticed
- delivered to postmaster(_at_)pobox(_dot_)com ===> postmaster will have to
manually track down a person capable of addressing the situation. If
he manages millions of accounts, he will not have time to bother.
IOW: this is a problem that has
nothing to do with SPF. The forwarding user screwed up. This is a good
reason BTW why the author should not be bothered by bounces.
What if the forwarding user just happened to get an unusually high
number of spams, that filled up his mailbox? Or what if some other
problem happend at his mailbox (such as: host unreachable due to
network problems beyond the receiver's control?).
If the message author is made aware, he/she can take action (send
message again hoping that problem is solved; use a different
communication channel such as the phone; ...)
Alex
Alain
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