Hlzatok 4 Lengyel Zsolt TCP UDP ICMP IGMP

Hálózatok 4. Lengyel Zsolt TCP, UDP, ICMP, IGMP Protocol ARP, DHCP, DNS, VPN Protocol Routing, Routing protocols (RIP, OSPF, BGP)

Protokoll Egyezmény, vagy szabvány, amely leírja, hogy a hálózat résztvevői miképp tudnak egymással kommunikálni RFC Internet Standards https: //www. rfc-editor. org/rfc-index. html IP TCP UDP HTTP, HTTPS …… FTP IEEE Standards http: //standards. ieee. org 802. 3 801. 11

Client-Server Vs Peer-to-Peer Web, Mail, FTP, SSH, …. Bittorrent

Transmission Control Protocol 7. Application 4. Application TCP 6. Presentation 5. Session 4. Transport 3. Transport 2. Internet Connection Oriented 3. Network 1. Network Interface (Link) 3 way handshake 2. Data Link 1. Physical SYN ACK Server Listening: TCP Port 80 Client DST MAC SRC MAC DST IP SRC IP DST Port SRC Port Seq ACK Frame IP TCP Packet Segment DATA CRC

Transmission Control Protocol 7. Application TCP 6. Presentation 5. Session 4. Application 3. Transport Connection Oriented 4. Transport 2. Internet 1. Network Interface (Link) 4 way disconnect 3. Network 2. Data Link 1. Physical ACK FYN ACK RST Server Listening: TCP Port 80 Client ip. dst == 192. 168. 1. 10 or ip. src == 192. 168. 1. 10 DST Port SRC Port Seq ACK TCP Segment DATA

Sliding Windows Window Size = 5 Buffer 1 2 3 4 5 1 2 4 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Ack 6 6 7 8 9 10 10 Byte File Workstation 1 Workstation 2

Sliding Windows Standard Acknowledgement Buffer 1 2 3 4 5 6 7 8 9 Buffer 1 2 3 4 5 6 7 8 10 9 10 11 12 13 14 15 16 10 Byte File Workstation 1 Ack 7 7 8 9 10 Ack 11 FIN-ACK ACK 10 Byte File Workstation 2

Sliding Windows *(Sequence Number) Selective Acknowledgement Buffer 1 2 3 Buffer Ack 11 - SACK 6 -8 1 2 4 3 4 5 6 7 8 9 10 11 12 13 14 15 16 10 Byte File Workstation 1 7 Ack 11 FIN-ACK ACK 10 Byte File Workstation 2

User Datagram Protocol 7. Application UDP 6. Presentation 5. Session 4. Application 3. Transport Connectionless 4. Transport 2. Internet 1. Network Interface (Link) 3. Network 2. Data Link DATA 1. Physical DATA Server Listening: UDP Port 67, 68 Client pl: DHCP DST Port SRC Port Checksum Length UDP Datagram DATA

Netstat TCP state: Established Listening Time_wait Close_wait UDP state: Stateless, nincs state netstat -an | find “ESTABLISHED” netstat -an UDP netstat -ltpun | grep “ESTABLISHED”

NAT Network Addess Translation 178. 68. 15. 54 192. 168. 1. 12 8. 8 192. 168. 1. 12 178. 68. 15. 54 8. 8 DST IP SRC IP

PAT Port Addess Translation (Dynamic NAT with overload) Server IP: 8. 8 PC 2: 192. 168. 1. 13 178. 68. 15. 54 PC 1: 192. 168. 1. 12 8. 8 PC 1: 53687 80 DST IP SRC port DST port 8. 8 PC 2: 192. 168. 1. 12 178. 68. 15. 54 192. 168. 1. 13 178. 68. 15. 54 35784 53687 80 DST IP SRC port DST port Listening: TCP Port 80

Port Forwarding 178. 68. 15. 54 192. 168. 1. 10 Pl. : Port 80 192. 168. 1. 10: 80

Routing 192. 168. 15. 1 98. 201. 164. 215 R 1 98. 201. 164. 1 IF 3 IF 1 IF 4 IF 2 202. 190. 44. 11 192. 168. 15. 0/24 R 2 IF 1 R 3 172. 17. 3. 1 172. 17. 3. 0/24 R 1 routing táblája Address Netmask Gateway Interface Metric 192. 168. 15. 0 255. 0 0. 0 192. 168. 15. 1 100 172. 17. 3. 0 255. 525. 255. 0 172. 17. 3. 1 100 0. 0 98. 201. 164. 1 98. 201. 164. 215 10 202. 190. 44. 1 11 Port (Interface)

Routing PC 1 IP: 192. 168. 1. 10/24 F 0/0 IP: 192. 168. 1. 10/24 Router 1 MAC: 00: 1 c: 42: 00: 09 Router 1 Router 2 Routingtable Routing table PC 1 Routing C C C S S S MAC: 45: 25: 4 f: 9 c: 11: ab 172. 16. 10. 0/30 192. 168. 1. 0/24 F 0/1 F 0/0 192. 168. 1. 0/24 NIC 10. 0/24 172. 16. 10. 0/30 F 0/0 F 0/1 0. 0/0 -> 192. 168. 1. 10 192. 168. 10. 0/24 172. 16. 10. 1 10. 0/0 ->->172. 16. 10. 2 F 0/1 IP: 172. 16. 10. 1/30 MAC: aa: bb: dd: 3 d IP: 172. 16. 10. 2/30 F 0/1 MAC: 23: 7 f: 34: 8 d: 1 a: 22 Router 2 PC 2 IP: 10. 0. 0. 1/24 F 0/0 MAC: 12: 4 d: 22: 31: 23: 09 Source MAC IP: 10. 0. 0. 10/24 MAC: 32: 2 e: 13: ce: f 3: 45 Destination MAC aa: bb: dd: 3 d 12: 4 d: 22: 31: 23: 09 23: 7 f: 34: 8 d: 1 a: 22 00: 1 c: 42: 00: 09 32: 2 e: 13: ce: f 3: 45 45: 25: 4 f: 9 c: 11: ab Frame Header Source IP Destination IP 192. 168. 1. 10 10. 0. 0. 10 IP Header Data

ipconfig/all IPv 4 Address. . . : 10. 211. 55. 20(Preferred) Subnet Mask. . . : 255. 0 route print

ip a ip route

Routing Protokolok Dynamic routing Static routing Distance Vector • • • Link State RIP IGRP EIGRP • • BGP IS-IS OSPF

RIP Routing Information Protocol A Z B Y Distance Vector Protocol Interior Gateway Protocol HOP: ugrások száma Max 15 Ugrást képes kezelni X C

OSPF Open Shortest Path First A Area 0 Z B Y Link State Protocol Interior Gateway Protocol X C

BGP Border Gateway Protocol LAN Router Network(ISP)

BGP Border Gateway Protocol Autonomus System (AS) BGP Router AS AS Egy vagy több routerhálózat csoport, egyetlen kézben (ISP) Minden AS-nek van egy 32 bites azonosító száma Az AS-ek BGP-vel kommunikálnak egymás között BGP Router AS BGP Router ~ kb 50 000 AS

#learnabout https: //en. wikipedia. org/wiki/Address_Resolution_Protocol https: //en. wikipedia. org/wiki/Dynamic_Host_Configuration_Protocol https: //en. wikipedia. org/wiki/Routing https: //en. wikipedia. org/wiki/Network_address_translation https: //en. wikipedia. org/wiki/Routing_protocol