First, thanks to Lumpy for the suggestion about checking at phpBBHacks(http://phpbbhacks.com/searchresults.php ... &Submit=Go
), but no, I didn't find anything in there that looked promising for the topic-notification problem. These all seem to assume that the existing functions work, so they're more oriented to adding functionality.
Specifically, dmpp has tried one of the hacks - with and without further custom mods - without much luck. This hack seems more oriented to a potential problem with the sender's address, and my hosting service doesn't appear to have a problem with the origination address that the mail functions use. (Besides, I notice on the phpBBHack forums that there's some debate there whether this particular patch is compatible with phpBB versions above 2.0.4.) In any case, that hack doesn't seem to have fixed the notification-reply problem for dmpp.
dmpp pointed out that the mail works for mass e-mails. I hadn't thought to test this before, but I've confirmed that on the test system I'm using, the mass e-mails work. In this case, the TO, FROM, and REPLY-TO addresses are the board administrator's address. The recipients are (apparently) in the BCC.
Since the use of the BCC for the recipients seems the same in the topic-notification routine and in the mass-mailing routine, it does raise the question of why a different TO addressing scheme appears to be used for each. Specifically, I notice that on my un-MOD'd test forum, the mass e-mail uses the board administrator's TO address, presumably because the administrator would like to receive a copy of what he's sending to verify that the mailing went out. On the topic-notification e-mail that I receive from this forum (the phpBB support forum), it is addressed to "Undisclosed-recipients:" which is clearly
an invalid e-mail address and, for that matter, not even a valid e-mail address format.
In this day and age of service providers risking blacklisting of their mail servers from as little as one spam message, I can understand why hosting services might be uncomfortable with sending out messages from a shared server to obviously fictitious e-mail addresses. A separate issue is how many rules-based spam-blockers at the recipients' locations will block such a message, even if it's successfully sent. (I've confirmed that this isn't my problem in testing the topic-reply-notification e-mail.)
So it looks as though a promising approach is to understand where in the code (and why in the world) the mass e-mail TO address differs from the topic-reply-notification e-mail TO address, with the goal being to find some way of putting in some valid TO address on the topic-reply-notification e-mail. The TO address to be used probably needs not
to be the administrator's e-mail, since the administrator could become inundated on a large board. It should, however, be a validly formatted e-mail account that the administrator can set up to receive-and-drop all incoming mail.
I'm hopeful that this narrows down the code search a bit for those who know the phpBB code, and that someone can offer some guidance as to how to find it and how to change it (preferably without breaking it
Anyone have any insights/thoughts?