The %3 is the preservation of the optional +detail part of the original address. In general, +detail means that when
Sendmail gets an address like
user+detail@domain, then if domain is in class w (see step 7 below),
sendmail checks to see if
user+detail can be resolved, then falls back to just plain user if not. Thus all of:
- joe@yourdomain.com
- joe+foo@yourdomain.com
- joe+reallylongextrapart@yourdomain.com
-
- would all match the above entry, with %3 preserving the +detail part of nothing, +foo and +reallylongextrapart respectively.
- Multiple domains are allowed, and virtual addresses in each domain are independent. So for example, you could have:
- joe@yourdomain1.com localjoe
- joe@yourdomain2.com joe@othercompany.com
- joe@yourdomain3.com localjoe
- joe@yourdomain4.com error:nouser No such user here