On Wed, Jul 05, 2006 at 10:23:44PM +0200, Rainer Sigl wrote:

Well, the From: header is different from the envelope return-address (which is MAIL FROM during a SMTP transaction)

Now you UTSL (Use The Source, Luke [TM])

Looking at sendit.sh.in, it invokes the MTA using

exec @mailer@ $DSN -f "$1"

So, the return-address is $1, the first argument passed to the script. The From: header is separate, and is passed in on stdin along with the rest of the headers and the message body.

grepping for 'sendit' you find this is run from newmsg.c, where the return address is generated by login_returnaddr():

returnaddr=login_returnaddr(); execl(SENDITSH, "sendit.sh", returnaddr, sqwebmail_mailboxid, NULL);

login_returnaddr() is defined in auth.c. This gets the contents of the AUTHADDR environment variable, which is the login name the user entered to login to sqwebmail. If it doesn't contain '@', then '@' myhostname() is appended.

So, the From: address which the user chooses, is not related to the return address on the mail.

Hopefully, it is clear why from above.

Well, you don't need this hack if you just want to append a different domain to the username. You can simply create a file $(sysconfdir)/hostname containing the domain you want appended, and this is used to build the return address. This is documented in the INSTALL file. If you don't create this file, then myhostname() falls back to using the gethostname() system call, to get the machine's actual hostname.

However, if the user changes the From: header to something completely different, say xy...@hotmail.com, the return address will still be logi...@mpe.mpg.de

Alternatively, it may be possible to invoke or configure exim in such a way that the return address is extracted from the From: header. I haven't dug into this. Or you can modify newmsg.c to call login_fromhdr() instead of login_returnaddr() to pass to sendit.sh

HTH,