Static Routing Exercise u Unix network interface configuration u Cisco network interface configuration u Static routes u Default route u Testing

A C B FE I G D H J RouterPC HUB RouterPC HUB RouterPC HUB Router PC HUB RouterPC HUB Router PC HUB Router PC HUB Router PC HUB Router PC HUB Router PC HUB SWITCH Classroom Layout

A C B FE I G D H J SWITCH / / / / / / / / / /28 Address Allocation /

Address Allocation u You already have an IP address for your router’s backbone link (A=.17, B=.18, …) u You have a /28 for your local network (PC and router connected to hub) u Allocate your own host addresses from your local /28 network

Network interface configuration - FreeBSD u configure interface on Unix host ifconfig fxp0 inet n.n.n.n netmask m.m.m.m –fxp0 is interface name –n.n.n.n is IP address –m.m.m.m is netmask

Connect PC to router console u Connect cable to console port on router, serial port on FreeBSD box u Use the tip command to connect your keyboard and screen to the serial port u You may have to edit /etc/remote u See man pages for tip(1) and remote(5)

Network interface configuration - Cisco u configure backbone interface on cisco router conf t interface ethernet0/0 ip address n.n.n.n m.m.m.m –ethernet0/0 is interface name –n.n.n.n is IP address –m.m.m.m is netmask u configure local interface on cisco router –ethernet0/1

Network interface configuration - Cisco u Cisco global config should always include: ip classless ip subnet-zero u Cisco interface config should usually include: no shutdown no ip proxy-arp no ip redirects

Test connectivity u PC can ping local interface of router u Router can ping PC u PC cannot ping backbone interface of router u Router can ping other routers u PC cannot ping other routers or other PCs

Add default route u Add route on PC route add default g.g.g.g –g.g.g.g is IP address of gateway (which is on cisco router) u Display forwarding table netstat -f inet -rn

Test connectivity u All PCs can now reach backbone IP address of own row u Still can’t reach other rows –why?

Add static routes to other rows u On router, add static routes to other rows –next hop is backbone interface of other row’s router ip route n.n.n.n m.m.m.m g.g.g.g u Repeat many times

Test connectivity u All routers can reach all PCs u All PCs can reach all backbone IP addresses u All PCs can reach PCs in other rows u Test with traceroute

Edit FreeBSD /etc/rc.conf u Don’t do this on classroom machines u On production machines, add lines to /etc/rc.conf to configure network on reboot hostname="porcupine.tomato.example" ifconfig_fxp0="inet netmask " defaultrouter=" " u See /etc/default/rc.conf for more information