Routing Information Protocol

Sniffing and Evasion

In this tutorial, we will set up and configure Routing Information Protocol (RIP) in GNS3. The objective is to establish dynamic routing between routers and a virtual private cloud (VPC1) using RIP.

Step 1: Understanding the Network Topology

Our network consists of:

• Router R1 (Connected to R2 via Serial 1/0)

• Router R2 (Connected to R1 via Serial 1/0 and to VPC1 via FastEthernet 0/0)

• VPC1 (Simulating a client machine, connected to R2 via FastEthernet 0/0)

Device	Interface	Address	Subnet Mask
R1	Serial 3/0	192.168.1.1	255.255.255.0
R2	Serial 3/0	192.168.1.2	255.255.255.0
R2	FastEthernet 0/0	172.16.1.1	255.255.0.0
VPC1	Virtual Interface	172.16.1.100	255.255.0.0

Toplogy

Step 2: Configuring Router R1

R1#configure terminal
R1(config)#interface serial 3/0
R1(config-if)#ip address 192.168.1.1 255.255.255.0
R1(config-if)#no shutdown
R1(config-if)#exit
R1(config)#router rip
R1(config-router)#network 192.168.1.0

Step 3: Configuring Router R2

R2#configure terminal
R2(config)#interface serial 3/0
R2(config-if)#ip address 192.168.1.2 255.255.255.0
R2(config-if)#no shutdown
R2(config-if)#exit
R2(config)#interface fastEthernet 0/0
R2(config-if)#ip address 172.16.1.1 255.255.0.0
R2(config-if)#no shutdown
R2(config-if)#exit
R2(config-router)#network 192.168.1.0
R2(config-router)#network 172.16.0.0

Step 4: Configuring VPC1 (Client Machine)

PC1> ip 172.16.1.100/16 172.16.1.1
Checking for duplicate address...
PC1 : 172.16.1.100 255.255.0.0 gateway 172.16.1.1

PC1> show ip

NAME        : PC1[1]
IP/MASK     : 172.16.1.100/16
GATEWAY     : 172.16.1.1
DNS         :
MAC         : 00:50:79:66:68:01
LPORT       : 20010
RHOST:PORT  : 127.0.0.1:20011
MTU         : 1500

PC1>

Step 5: Verify connectivity with a ping test

PC1> ping 172.16.1.1

84 bytes from 172.16.1.1 icmp_seq=1 ttl=255 time=30.814 ms
84 bytes from 172.16.1.1 icmp_seq=2 ttl=255 time=8.786 ms
^C
PC1> ping 192.168.1.2

84 bytes from 192.168.1.2 icmp_seq=1 ttl=255 time=9.390 ms
84 bytes from 192.168.1.2 icmp_seq=2 ttl=255 time=8.624 ms
^C
PC1> ping 192.168.1.1

84 bytes from 192.168.1.1 icmp_seq=1 ttl=254 time=31.406 ms
84 bytes from 192.168.1.1 icmp_seq=2 ttl=254 time=27.448 ms
^C
PC1>

Step 6: Capture RIP packets using Wireshark

Apply a filter:

rip

Verify that RIP advertisements are being broadcast correctly.

Step 7: Understanding RIP

Key Features of RIP:

• Distance-vector routing protocol

• Uses hop count as a metric (max 15 hops)

• Broadcasts routing table every 30 seconds

• Uses UDP port 520

• Administrative distance: 120

Keywords

RIP, Routing Information Protocol, GNS3, dynamic routing, router configuration, IP addressing, subnet mask, hop count, distance-vector, routing table, serial interface, FastEthernet, VPC1, network topology, debug ip rip, show ip route, routing updates, UDP port 520, administrative distance, RIP packets, وایرشارک