I want to deploy my ASP.NET web service with EC2 on AWS. Is there any way to prevent DDos attacking?
There are several dedicated DDOS prevention services out there. I would start with CloudFlare + Dome9 combination - both services have a free tier.
Cloudflare will act as the public end point/ DDOS mitigation front-end, while Dome9 will make sure no one bypass Cloudflare for your 80/443 ports, and will keep your private administrative ports (RDP) stealth.