1. How to connect to the Internet 1998/12/09 KEIO University, JAPAN Mikiyo Nishida/west@sfc.wide.ad.jp

2. Overview of this section Internet connectable hardware/OS Why use the UNIX OS? Host connect to the network Server side configuring

3. Internet connectable hardware Hardwares –Workstation –PC (Personal Computer) –Set Top Box –Game machine and others –PDA

4. Internet connectable OS UNIX Family –FreeBSD –BSD/OS –Linux –SunOS Windows Family –Windows 95/98 –Windows NT

5. Why use the UNIX OS? The Internet was developed on UNIX UNIX’s TCP/IP stack, and service daemons are more reliable than Windows but, Windows can connecting network easy...Generally Front-end : Windows or UNIX Back-end : UNIX

6. Host connect to the network Configuring Network Interface Configuring Routing Table Configuring Name Resolver Automatic network configuration

7. Configuring Network Interface Network Interface has global unique IP Address Host is belong to a network - Network Interface has netmask

8. Setting IP Address and Netmask Use command “ifconfig” “ifconfig” command attach/detach/modify NIC’s network information –example: # ifconfig ed0 inet 192.168.1.2 netmask 255.255.255.0

9. IP Address and Netmask IP Address is separated 2 parts –Host Address Indicate Host ID –Network Address Indicate Network ID host belong Netmask indicates Network Address part of IP Address

10. Special IP Address(1) Private IP Address –Not use for global Internet 10.0.0.0 - 10.255.255.255 172.16.0.0 - 172.16.255.255 192.168.0.0 - 192.168.255.255 Localhost (indicate MYSELF) 127.0.0.1

11. Special IP Address(2) Datalink Broadcast Address –All nodes in the same network segment 255.255.255.255 Network Address –Host Address part’s all bit are 0 192.168.1.0 / netmask 255.255.255.0 Network Broadcast Address –Host Address part’s all bit are 1 192.168.1.255 / netmask 255.255.255.0

12. Configuring Routing Table For the communication, Host must send packet to router Routing Table is used where send the packet.

13. Setting Route in Routing table Command “route” set/unset/change route in routing table –example #route add 192.168.0.0 10.0.0.1 #route add default 192.168.1.2

14. Routing Table Routing table has mapped data route (Destination Network - Next Hop Router) “default route” is route for unknown destination network Generally, End-node (Host) set “default route” to border router

15. Configuring Name Resolver TCP/IP Stack must resolve the matching hostname and IP Address For resolving, TCP/IP stack queries DNS Server

16. Name Resolver Setting Name Resolving DNS Server is describing “/etc/resolv.conf” If use statically hostname and IP Address table, describe “/etc/hosts”

17. Example of Name Resolver Setting /etc/resolv.conf DOMAIN sfc.wide.ad.jp NAMESEREVR 202.217.0.99 SEARCH sfc.wide.ad.jp. wide.ad.jp. /etc/hosts myhost192.168.9.8 yourhost10.0.0.1

18. Automatic Host Configuration DHCP - Dynamic Host Configuration Protocol –Automatically configure host setting IP Address Netmask DNS Server Address Default Route

19. Server side configuration DNS (bind) Entry Routing Daemon