Introduktion till IP – Internet Protocol - SE

Innehåll
TCP och UDP-nivån 59
Portnummer ....................................................................... 59
Handskakning .................................................................... 63
Dela upp dataflödet i paket ................................................ 64
TCP Headern ..................................................................... 65
TCP optioner ..................................................................... 67
Flödeshantering .................................................................. 68
Hur fungerar UDP? ........................................................... 70
Nivå fyra och framtiden ...................................................... 72
Referenser .......................................................................... 72
IP-baserade program 73
Telnet ................................................................................. 73
Secure Shell – SSH ............................................................. 75
File Transfer Protocol – FTP ............................................... 75
HyperText Transfer Protocol – HTTP ................................ 77
Säkerhet på applikationsnivå .............................................. 80
Referenser .......................................................................... 80
Domain Name System – DNS 81
Hosts-filen .......................................................................... 82
Namnstrukturer ................................................................. 82
Toppdomäner .................................................................... 83
Resolvers ........................................................................... 86
Fråga och svar ..................................................................... 87
Baklängesuppslagning ........................................................ 90
Säkerhet och DNS .............................................................. 90
Referenser .......................................................................... 91
Adressöversättning 93
Privata adresser ................................................................... 94
NAPT ................................................................................ 95
Port Forwarding eller Port Address Translation – PAT ....... 96
Network Adress Translation – NAT ................................... 97
Adressöversättning ger ett visst skydd ................................ 98
Problem med adressöversättning ........................................ 98
Klienter som loggar på ..................................................... 100
Wrap around-problemet ................................................... 101
Adressöversättning och applikationer ............................... 102
Fördjupning: tre olika former av NAPT ........................... 103
Referenser ........................................................................ 108
introduktion till ip