Charles Boling:
> 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.
Address transformation mappings are always queried at recipient
validation time, so you can't use a wild-card pattern to replace
"_" by "+" without becoming a backscatter source.
The only way to change an envelope address before SMTP server
recipient validation is with the Postfix 2.7 smtpd_command_filter
which replaces SMTP commands before they are executed. This is
for the desperate. It has no safety mechanisms.
http://www.postfix.org/postconf.5.html#smtpd_command_filter
Wietse
> 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?
>
>
>
