I'm still on 1.2.whatever, actually. I guess I posted in the wrong forum...whoops!

Anyhow - punBB uses php's built-in mail() function if no SMTP server is defined, right? Is there some other config setting other than config.php and the config table in the database that I need to manually change? I'd really rather not dump my entire DB, if I can help it.

Nope. I didn't change anything about the configuration - just the URL. Email worked fine before I changed the URL.

I already fixed that, and made sure that the cached config file was also updated.

It's not just registration emails - I tried sending myself an email through the interface, and it never sent.

I changed my punBB installation's URL from foo.com/forum/ to forum.foo.com, and it would appear that since that change, registration emails (containing the user's initial password) are no longer being sent.

I've looked at some of the files but can't seem to see where to fix this. I'm not using any SMTP settings; just the internal mail() function.

I haven't found anything on Google about this, so apologies if it's a repost.