We actually already use sendmail in other recipes, so that's fine.
We still need a way to choose the correct From: address though.

I don't think that maildrop could work without a sendmail compatible 
binary , but I'm not sure.

The feature could be added as an option.
Thanks

This would assume that sendmail or at least some sendmail compatible 
binary is installed.

Hi,

when using ingo and maildrop for forward email to an external address 
Ingo creat a filter like this:

if( \
    /^From:\s*.*/:h \
)
exception {
   cc "! alessio.cecchi@gag.it"
  exit
}

but in this mode the email has return-path empty (<>) and this can 
cause some email to reject from some email server

we can set

exception {
   cc "| /usr/sbin/sendmail -fMY@address REMOTE@address"
  exit
}

that add the correct return path. Could be nice add the option for set 
or not set the return-path in forwarded messages.

You can also read this:
http://markmail.org/message/n3c6tx45j5o3mhsr

Thanks