L3->

i can never seem to remember the order in which protocols are applied from L2 and upward. some hacky notes to help me along.

DNS HEADER:

ID

OR | OPCODE | AA | TC | RD | RA | Z

QDCOUNT 1

ANCOUNT 0

NSCOUNT 0

QNAME:  ?google.com?

QTYPE:

QCLASS:

UDP Header:

Source Port, Destination Port

IP HEADER

VERSION(4) IHL ToS TTL(>0) Identification FLAGS

Route table -> find destination IP of the DNS server -> default -> GATEWAY -> [router] -> (((ETHERNET<->MAC ADDRESS)))

HUB < modern == SWITCH >

ROUTER < default gateway -> eth1 ->rewrite private IP -> public IP  -> NAT -> goes to ethernet frame -> PPPoE -> On to the wire…...

DNS RESPONSE  over TCP [ack, three-way handshake]-> Congestion control) -> SYN, SYN-ACK, ACK -> send 1...10, ACK 10, Send 11 … 20, ACK 15, Send 15 …. 24, ACK 2x….

:::: HTTPS ::: (  client hellp --> server → server hello + cert _ serverkeyExchange → ServerHelloDone → ClientKeyExchange -> ChangeCipherSpec -> Finished ) -> (TLS-wrapper [http GET www.google.com] )