OK, I'll bite.

Scott Pack did an excellent job explaining the situation, but since I was one of the ones voting to close the question, I figured I should weigh in.

My reasoning for voting to close are thus: you admitted that you were doing this in a home environment, on non-professional gear, on a dynamic IP address, for the purposes of familiarizing yourself with the technology. Understood, and that's certainly a noble goal. However, you'd be learning wrong. Doing what you propose would be like someone wanting to become an auto mechanic and deciding to go out and buy a remote control car to "learn" on. Sure, you are going to learn some things working with the Synology and your dynamic IP, but then you're going to have to learn an entirely new set of skills when you go to host your application in production.

If you want to learn this stuff, do it right. Pony up for a real VPS to tinker with - a decent VPS (I heartily recommend Linode) will set up back no more than $20/month, and in addition to being able to run circles around your Synology box, it also is hosted on a real, multi-homed internet connection, on a static IP address, in a real datacenter. Learning in this environment will be **much** more productive for you, as you won't need to fight the technology (dynamic IP, spam blacklists, port forwarding, ISP downtime, etc.).

So, to conclude, my decision to close still stands, though not for the same reasons as I voted last night. When I placed the vote, it was not clear that this was for business purposes, and as such, was off-topic. Now that we know that this is indeed for business purposes (even though you aren't a sysadmin by trade), I still feel that it needs to stay closed due to the "it's just a really bad idea" factor. As a professional sysadmin, I (and others) here feel deeply that we need to speak strongly against Questions that ask about doing something in clearly the wrong way, or answers that recommend the same. I can't in good conscience tell you that what you propose is a good idea.