[SM-USERS] Problem sending mail to some strict MX's

[Thomas S. <th...@so...>]

Hi,

I just discovered a little flaw in the source-code of Squirrelmail 1.4.0
concerning SMTP transmission of e-mails.

When trying to send a message through one of our local mail-servers and
routing it from there towards a domain hosted by Tiscali Europe, it
stays in the local MX's queue forever (until it is returned, that is).

I found the problem to be in line 149 of
class/deliver/Deliver_SMTP.class.php.

Having changed it from
 fputs($stream, 'MAIL FROM: <'.$from->mailbox.'@'.$from->host.">\r\n");
to
 fputs($stream, 'MAIL FROM:<'.$from->mailbox.'@'.$from->host.">\r\n");

solves the problem.

The problem resides in the not entirely RFC-821 (SMTP) -compliant
implementation of the SMTP-protocol. Some mailserveres, including
Tiscali's, expect the sender-address to be enclosed in brackets and not
be separated from the command (MAIL FROM:) by any space of whatsoever
kind.

Thought you all might be interested.

/Thomas Skyt