where does ipsec reside in a protocol stack
IPsec IPsec is an end-to-end security scheme operating in the Internet Layer of the Internet Protocol Suite, while some other Internet security systems in widespread use, such as Transport Layer Security (TLS) and Secure Shell (SSH), operate in the upper layers at the Transport Layer (TLS) and the Application layer (SSH). IPsec can automatically secure applications at the IP layer.
Denial-of-service attack A wide array of programs are used to launch DoS-attacks.
HTTPS Everything in the HTTPS message is encrypted, including the headers, and the request/response load. With the exception of the possible CCA cryptographic attack described in the limitations section below, the attacker can only know that a connection is taking place between the two parties and their domain names and IP addresses.
IPv4 IPv4 uses 32-bit addresses which limits the address space to 4294967296 (232) addresses.