Staic IP's and routing through 3rd party Firewall
I noticed that one of my servers on my external static IP is constantly being bombarded with DDoS attacks. As soon as I take that server offline, the attacks stop and I can then connect to the internet successfully again.
Becuase of this, I decided that I am going to get a 3rd party firewall (Palo Alto PA-220) and use that to help remediate the DDoS attacks. However, an issue that I feel may happen is that I won't be able to use this firewall to manage the external IP address ranges becuase those are handled by the Cisco Gateway device that is provided by Comcast.
Talking with their Level 3 enginieers, they said that they do not support any other modem since the routes for the static IP's that I use are hard coded in that gateway that they provide me.
The question I have is if I were to change the router IP address from x.x.x.62 (my external gateway address) to say x.x.x.61, which would be the PAN, and then have the PAN's next hop be x.x.x.62 and then use the NAT in the PAN to handle the external IP's, would it work, or will I end up with IP address conflicts since the Comcast gateway handles these addresses?
Has anyone set anything like this up before where all routing was handled by a 3rd party firewall/router with static IP's provided by Comcast hardware?