Man this is the best kept secret in the entire telecoms industry … I've been trying to send email through PLDT's SMTP servers as I'm a broadband customer of theirs, and my normal SMTP server wasn't working. I needed to get an email out, and I was getting a little desperate.
So apparently the published SMTP servers don't actually work. Yay! If you try looking on the PLDT website, where you might expect to see this kind of useful information … well just don't bother. You get seasick pretty quickly from all the flash whoopiness, and the dead ends and 404 start to piss you off after a while. So then you do a few google searches and come up with a couple of published servers, which basically don't work: smtp.info.com.ph and smtp.pldtdsl.net
So, eventually I cracked and went to the Customer Hotline. After re-phrasing my question several thousand times until I was understood, the answer was … smtpdsl4.pldtdsl.net , using port 587. Which actually works.
Port 587, yes of course, why didn't I guess that one.