1. The ABC of Linux Networking By Peter Larsen FredLug
September 2012
2. Agenda Good old OSI 7 layers The IP Stack Networking
Examples Commands RHEL/CentOS/Fedora networking Ubuntu/Debian
anyone??
3. Good old OSI 7 layers Physical Data Link Network Transport
Session Presentation Application Physical Link Physical Data Link
Network Transport Session Presentation Application
4. Physical Layer Physical Data Link Network Transport Session
Presentation Application Physical Link Physical Data Link Network
Transport Session Presentation Application
5. Data Link Layer Physical Data Link Network Transport Session
Presentation Application Physical Link Physical Data Link Network
Transport Session Presentation Application
6. Network Layer Physical Data Link Network Transport Session
Presentation Application Physical Link Physical Data Link Network
Transport Session Presentation Application
7. Transport Layer Physical Data Link Network Transport Session
Presentation Application Physical Link Physical Data Link Network
Transport Session Presentation Application
8. Session Layer Physical Data Link Network Transport Session
Presentation Application Physical Link Physical Data Link Network
Transport Session Presentation Application
9. Presentation Layer Physical Data Link Network Transport
Session Presentation Application Physical Link Physical Data Link
Network Transport Session Presentation Application
10. Application Layer Physical Data Link Network Transport
Session Presentation Application Physical Link Physical Data Link
Network Transport Session Presentation Application
11. The IP Stack Internet Protocol Implements the network stack
Uses fewer layers than OSI (Application, Transport, Internet, Link)
End-to-end Principle Robustness Principle Was built to withstand
loss of nodes and not break the network
12. The IP Stack
13. The IP Stack
14. Networking Examples Physical Networks IP basic network IP
Package Gateways
15. Physical Network
16. IP Network
17. IP Package
18. Gateways
19. Concepts IP Address Internet Protcol Address (xx.xx.xx.xx)
MAC Address Media Access Control (xx:xx:xx:xx:xx:xx) Netmask
Indicates which part of IP address is network address Network
Address Nodes on the same network can talk to one another Node
Address Every node must have a unique address in it's network
Gateway System that can route traffic Switch/Hub Device to
interconnect multiple wires into a network DNS Domain Name System
translates names into IP (or visa versa) DHCP Dynamic Host
Configuration Protocol
20. Commands Commands to configure Commands to diagnose
21. Commands to configure ifconfig ip route arp
system-config-network (rhel/Fedora) /etc/resolve.conf
/etc/hosts
22. Commands to diagnose ip show / ifconfig route display
routes arp display current ARP table host / dig ping / traceroute
ethereal / wireshark
23. RHEL/CentOS/Fedora networking Easy way:
system-config-network Hard way: /etc/sysconfig/network-scripts
service network start|stop|restart ifup / ifdown Network
Manager