IPSec (2nd Edition)

While IPSec is a versatile and functional protocol for securing IP, it is not a complete solution for all deployments, and there are still other issues that may need to be addressed. Many protocols desire to use IPSec to satisfy their security concerns and these have different problems that IPSec addresses incompletely. Indeed, while IPSec is a solution to a large problem, it is a problem to other protocols for instance, network address translation (NAT).