over 100 scanner requests 5 min after domain registration

First off, I am no security expert!

Yesterday I registered a .cf domain, I needed it for about 10 minutes. About 5 minutes after domain registration I got over 100 scanner requests (I checked all requests, all are automated scanner requests like ZmEu etc.) in under 10 seconds.

1. Considering the amount in such a short period and so soon after registration, am I being targeted or is this kinda everyday business for a .cf domain?
2. All requests are exclusively over port 80. I had a few more ports (443,…) open. I am not sure how to interpret this?!
3. All my things are written in c/c++ (sockets, openssl,…), is there a up to date list or something about common attacks targeting specifically c/c++ servers and how to prevent them?

————–EDIT

I host the things on my own, on a few server. Further the services are always the same (same ports), same static ip, but only for a short period always linked to a different domain. And it was the first time I used a .cf domain. Now I am simply a bit afraid to repeat the process, because yeah if I am really beeing targeted I should check everything twice first.