1. Basic Linux Router I touch@coe.psu.ac.th

2. Router, a device that... Working on OSI Layer 3 (Network Layer) Connected to more than one networks Finding a best path to deliver packets Forward packets from one network to another Can run on either dedicated device or personal computer

3. Routing.. How it works. Default Gateway Routing Table Routing mechanism Static Routing Dynamic Routing

4. Default Gateway An address for host to deliver packet to, if source and destination host are not in the same subnet Default Gateway Example...

5. Routing Tables Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 202.12.74.192 0.0.0.0 255.255.255.192 U 0 0 0 eth1 192.100.77.0 172.30.0.1 255.255.255.0 UG 0 0 0 eth0 172.30.0.0 0.0.0.0 255.255.252.0 U 0 0 0 eth0 192.168.0.0 172.30.0.1 255.255.0.0 UG 0 0 0 eth0 172.16.0.0 172.30.0.1 255.240.0.0 UG 0 0 0 eth0 0.0.0.0 202.12.74.193 0.0.0.0 UG 0 0 0 eth1

6. Routing Mechanism Static Routing Dynamic Routing Interior Routing Protocol RIP, OSPF, IGRP Exterior Routing Protocol BGP, EIGRP

7. Routing Devices Dedicated Devices Enterprise Cisco, 3COM, Juniper, Huawei, etc. SOHO Various broadband router. PC based Devices Linux Router

8. Linux Router command ifconfig [-v] [-a] [-s] [interface] route [-CFvnee] route [-v] [-A family] add [-net|-host] target [netmask Nm] [gw Gw] [metric N] [mss M] [window W] [irtt I] [reject] [mod] [dyn] [reinstate] [[dev] If] route [-v] [-A family] del [-net|-host] target [gw Gw] [netmask Nm] [metric N] [[dev] If] route [-V] [--version] [-h] [--help]

9. Linux Router command ping [ -LRUbdfnqrvVaAB] [ -c count] [ -i interval] [ -l preload] [-p pattern ] [ -s packetsize] [ -t ttl] [ -w deadline] [ -F flowlabel] [ -I interface] [ -M hint] [ -Q tos] [ -S sndbuf] [ -T timestamp option] [ -W timeout] [ hop...] destination traceroute [ -dFIlnrvx ] [ -f first_ttl ] [ -g gateway ] [ -i iface ] [ -m max_ttl ] [ -p port ] [ -q nqueries ] [ -s src_addr ] [ -t tos ] [ -w waittime ] [ -z pausemsecs ] host [ packetlen ]