this is what i found somewhere on internet :
The problem could be a header problem and a certain linux-dictribution could not handle this. Is this possible ?
There seems to be lots of confusion about general e-mail and sendmail
issues. Here’s my attempt to clear some of them up.
1. Line terminators.
The RFC states that the line terminator for SMTP is \r\n. If PHP just
passes the message string to the MTA unparsed, you must use \r\n to
indicate line breaks in headers and the body. Some MTAs e.g. sendmail
can understand \n on its own and can even be configured to fix the
problem – but don’t rely on it.
2. -f <sender address>
This is a sendmail option to set the envelope sender. It is a so
called privileged option because if any Unix user could issue it, they
could easily impersonate any login account on the server. This is why
setting the user under which apache is running to be a trusted user
allows you to use this option (because sendmail is being invoked by
the apache user). You can, of course set any headers you like using
the mail() function. These can include the From, Reply-to and
Return-path headers. If these are already in the mail when sendmail
sees them, they will not be added or altered. Most mail user agents
will display these in preference to the envelope sender.
3. “From” in the text of the mail.
One poster has suggested you don’t begin lines with the word “From”
because it gets munged with a “>”. In fact this is nothing whatsoever
to do with SMTP which is perfectly capable of handling such lines.
The “problem” is legitimate functionality of the standard Unix local
delivery agent. With normal Unix mail boxes – which are flat text
files, each message starts with a line consisting of the word “From”
and then the envelope sender and the date received. The “>” is
inserted by the delivery agent to prevent normal text lines from being
interpreted as the start of a new message. The mail user agent should
take the “>” out again.
