I suddenly started having with issues where Gmail and Hotmail were blocking emails sent by my forum using my email server. Emails sent from this same email server by me using Thunderbird or anyone else, where not blocked. So somehow it was the way FUDforum was constructing the email headers. The reasons for blocking where RFC2822 (Gmail) and RFC5322 (Hotmsil). It turns out RFC2822 was superseded by RFC5322 (as RFC822 was superseded by RFC2822).
I found an online email header checker (here is one although not what I used http://mxtoolbox.com/public/tools/emailheaders.aspx). Comparing the headers Thunderbird would create verse FUDforum found that they both had errors in the checker but FUDforum headers had this: "WARNING: duplicate header 'From' at line 21". So I looked into the code for FUDforum and found where it was adding a From header and commented out. This file is $DATA_FOLDER/src/iemail.inc.t which will fix this for all of your themes. Recompiled the theme and voila! Fixed.
All of this is in this thread: http://fudforum.org/forum/index.php?t=msg&goto=183103
PATCH:
--- src/iemail.inc.t-orig 2013-09-23 04:14:00.680024261 +0000
+++ src/iemail.inc.t 2013-09-23 04:13:43.409824908 +0000
@@ -63,7 +63,8 @@
if (strpos($header, 'MIME-Version') === false) {
$extra_header = "\nMIME-Version: 1.0\nContent-Type: text/plain; charset=utf-8\nContent-Transfer-Encoding: 8bit". $header;
}
- $header = 'From: '. $from ."\nErrors-To: ". $from ."\nReturn-Path: ". $from ."\nX-Mailer: FUDforum v". $GLOBALS['FORUM_VERSION']. $extra_header. $header;
+ //$header = 'From: '. $from ."\nErrors-To: ". $from ."\nReturn-Path: ". $from ."\nX-Mailer: FUDforum v". $GLOBALS['FORUM_VERSION']. $extra_header. $header;
+ $header = $extra_header. $header;
$body = str_replace("\r", '', $body);
if ($munge_newlines) {
UPDATE: I found the email header checker site I used: http://www.apps.ietf.org/content/message-lint