Hi, today we will look for some networking stuff. Up to now, I have not written any routing-related technical post. In this article, I am gonna show you some simple dynamic routing with RIP protocol. Routing is divided into two part which one is static. In static routing, routes are configured in the router by typing every detail of the route and all things configured are used in routing. But in dynamic routing, we configure the general rules and then let the network generate specific rules according to the config.
For example, if you need to statically route A, B, C networks through D network you should write separate route all of the three networks in each router. But in dynamic routing, you should only write three route in one router. Other routers get theses routes with dynamic routing protocols. Now let start typing commands.
Set Static IP Addresses For Interfaces
First, we need to configure the IP address of the interfaces that play in routing.
R1#configure Configuring from terminal, memory, or network [terminal]? Enter configuration commands, one per line. End with CNTL/Z. R1(config)#interface ethernet 0/0 R1(config-if)#ip address 10.1.0.1 255.255.255.0 R1(config-if)#no shutdown R1(config-if)#exit R2#configure Configuring from terminal, memory, or network [terminal]? Enter configuration commands, one per line. End with CNTL/Z. R2(config)#interface ethernet 0/1 R2(config-if)#ip address 10.2.0.2 255.255.255.0 R2(config-if)#no shutdown R2(config-if)#exit R3#configure Configuring from terminal, memory, or network [terminal]? Enter configuration commands, one per line. End with CNTL/Z. R3(config)#interface ethernet 0/0 R3(config-if)#ip add 10.1.0.2 255.255.255.0 R3(config-if)#no shutdown R3(config-if)#exit R3#configure Configuring from terminal, memory, or network [terminal]? Enter configuration commands, one per line. End with CNTL/Z. R3(config)#interface ethernet 0/1 R3(config-if)#ip address 10.2.0.1 255.255.255.0 R3(config-if)#no shutdown R3(config-if)#exit
Check Connectivity
Now we should check the L3 connectivity. One direction check is enough
R1>ping 10.1.0.2 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 10.1.0.2, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/1 ms R3#ping 10.2.0.2 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 10.2.0.2, timeout is 2 seconds: .!!!! Success rate is 80 percent (4/5), round-trip min/avg/max = 1/1/1 ms
Enable RIP Routing Service
Now we can start describing networks for routing. With network command, we specify network that will be used for rip routing. There are two main effects of this command. First, we specify that this network will be used for rip routing which means this network address will be learned by other routers. Second the interface this network belongs to start to rip communication like sending and receiving rip packets. Auto-summary command makes routing classfull which is generally not used today so we disable it with no auto-summary command. If you have problem with rip routing look first this auto-summary option.
R1(config)#router rip R1(config-router)#network 10.1.0.0 R1(config-router)#no auto-summary R1(config-router)#exit
Troubleshoot RIP Protocol
To see that rip protocol works we can debug rip packets with debug IP route command. We see that rip is sending packets but not receiving yet because we didn’t configure other routers.
R1#debug ip rip RIP protocol debugging is on R1# *Oct 11 04:05:58.871: RIP: sending v1 update to 255.255.255.255 via Ethernet0/0 (10.1.0.1) *Oct 11 04:05:58.871: RIP: build update entries - suppressing null update
Configure RIP On Interface
Now it is time to configure R3. so we can set neighbor-ship with R1 and see the RIP in work. As you can see after describing network R3 created neighbor-ship with R1
R3(config)#router rip R3(config-router)#network 10.1.0.0 *Oct 11 04:08:25.865: RIP: sending request on Ethernet0/0 to 255.255.255.255 *Oct 11 04:08:25.865: RIP: sending request on Ethernet0/1 to 255.255.255.255 R3(config-router)#no auto-summary *Oct 11 04:08:27.863: RIP: sending v1 flash update to 255.255.255.255 via Ethernet0/0 (10.1.0.2) *Oct 11 04:08:27.864: RIP: build flash update entries *Oct 11 04:08:27.864: subnet 10.2.0.0 metric 1 *Oct 11 04:08:27.864: RIP: sending v1 flash update to 255.255.255.255 via Ethernet0/1 (10.2.0.1) *Oct 11 04:08:27.864: RIP: build flash update entries *Oct 11 04:08:27.864: subnet 10.1.0.0 metric 1 R3(config-router)#exit
Print/List RIP Configuration and Information
If you look to rip database and routing table you will see a new route is added. The new route id sends from R3 to R1. The new route is the et0/1 interface and network of R3. Then we ping to the IP of the new route. sh ip rip database command shows rip database. show ip route command shows routing table.
R1#sh ip rip database 10.0.0.0/8 auto-summary 10.1.0.0/24 directly connected, Ethernet0/0 10.2.0.0/24 [1] via 10.1.0.2, 00:00:18, Ethernet0/0 R1#show ip route Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 E1 - OSPF external type 1, E2 - OSPF external type 2 i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2 ia - IS-IS inter area, * - candidate default, U - per-user static route o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP a - application route + - replicated route, % - next hop override Gateway of last resort is not set 10.0.0.0/8 is variably subnetted, 3 subnets, 2 masks C 10.1.0.0/24 is directly connected, Ethernet0/0 L 10.1.0.1/32 is directly connected, Ethernet0/0 R 10.2.0.0/24 [120/1] via 10.1.0.2, 00:00:24, Ethernet0/0 R1#ping 10.2.0.0 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 10.2.0.0, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/1 ms