Undelivered Mail 01.25.06
Many users have, at one point, received notices of undelivered
mail which they have never personally sent. This is usually
Let there be three persons, "A", "B", and "C". Assume you are
- An email-spreading virus infects the PC of Person C. The
virus harvests the contents of Person C's addressbook(s),
which happens to have the email addresses of Persons A and B.
- The virus will now begin creating and sending out forged
emails. One of these happens to have Person B as recipient
and Person A as sender.
- The mail server handling Person B's email receives the
forged, infected message. The server has anti-virus software
- The anti-virus software detects the virus and rejects the
message. Per standard email server behavior, an undelivered
notice is sent to the forged sender of the email, namely
- Person A's mail server receives the undelivered notice,
and promptly delivers it to Person A's inbox.
Note how Persons A and B are innocent bystanders in this whole
affair. This is how undelivered mail that we never sent finds
its way into our mailbox, and is an unfortunate fact of life
on the Internet.