i've never done anything like this before im mostly used to using VPS servers to make a vpn but i wondering how i would be able to setup a softether vpn server using big-ip. im mostly interested in the ddos protection aspect of silverline. that would mostly be the point of the vpn.
could anyone help me out with this?
You need to provide more details of what you are wanting to do.
BigIP does not directly support Softether VPN - the best you could do is use BigIP passthrough virtual servers to loadbalance connections to the Softether VPN servers.
You could use AFM DDoS protection for L3.
Silverline primarily provides ASM for web applications, and would only provide L3 DDoS protection for a VPN. You would need to raise your queries regarding how suitable Silverline was directly with the Silverline team.