I've been a postfix user for nearly 10 years, but in many ways I'm still
quite the newbie. That's the problem with Postfix being such a solid
MTA: I don't mess with it much. :-)
For a good chunk of that time, I have wrestled on and off with this
problem off and on, playing with it for a bit, giving up, then returning
to it a year or two later. After all this time, I've finally gotten
smart enough to specifically ask for help!
I love "+" addressing, the ability to append ad-hoc suffixes to an email
address (like the one used to post to this list). The problem is, a lot
of web sites don't. They tend to take the lazy route to preventing SQL
injection attacks, and reject any address with a "+" in it.
To address that issue, I would like to be able to use another character
("_" or ".") that is commonly accepted as part of email addresses, instead.
When an email comes into Postfix (v2.2 currently), I would like it to
search for, e.g. "_" in the recipient address, and replace it with "+".
This, of course, needs to happen before it does recipient checking.
The validated message is eventually passed on to the MDA (Cyrus, in my
case) with the "+" in it.
How might be the best way to accomplish this?
