Three Routers Configuration Using Serial Port with Static IP (2025)

three routers configuration with serial port with static ip configuration with commands 2025This complete guide explains how to configure three routers connected via serial ports using static IP addressing, step by step, with Cisco IOS commands. This is useful for:

• Networking students
• CCNA preparation
• Interview practice
• Lab configuration (Packet Tracer / real routers)

---

1. Network Topology Overview

three routers configuration with serial port with static ip configuration with commands 2025

We will configure 3 routers connected in a linear topology using serial DCE/DTE cables.

PC1 ---- R1 ---- R2 ---- R3 ---- PC2
        S0/0/0  S0/0/1  S0/0/0

• Router 1 (R1) connected to Router 2 (R2)
• Router 2 (R2) connected to Router 3 (R3)
• Static IP addresses on all interfaces

---

2. IP Addressing Scheme (Static)

three routers configuration with serial port with static ip configuration with commands 2025

LAN Networks

Device	Interface	IP Address	Subnet Mask
PC1	NIC	192.168.1.2	255.255.255.0
R1	G0/0	192.168.1.1	255.255.255.0
PC2	NIC	192.168.3.2	255.255.255.0
R3	G0/0	192.168.3.1	255.255.255.0

Serial Links

Link	Interface	IP Address	Subnet Mask
R1–R2	R1 S0/0/0	10.0.12.1	255.255.255.252
R1–R2	R2 S0/0/0	10.0.12.2	255.255.255.252
R2–R3	R2 S0/0/1	10.0.23.1	255.255.255.252
R2–R3	R3 S0/0/0	10.0.23.2	255.255.255.252

---

3. Hardware & Software Requirements

three routers configuration with serial port with static ip configuration with commands 2025

• Cisco Routers (1841 / 2811 / 2911)
• Serial DCE/DTE cables
• PCs or laptops
• Cisco Packet Tracer / GNS3
• Cisco IOS

---

4. Basic Router Configuration (All Routers)

three routers configuration with serial port with static ip configuration with commands 2025

Perform these steps on each router.

enable
configure terminal
hostname R1   # Change for R2, R3
no ip domain-lookup

---

5. Router 1 (R1) Configuration

three routers configuration with serial port with static ip configuration with commands 2025

Configure LAN Interface

interface gigabitEthernet0/0
ip address 192.168.1.1 255.255.255.0
no shutdown
exit

Configure Serial Interface (DCE)

interface serial0/0/0
ip address 10.0.12.1 255.255.255.252
clock rate 64000
no shutdown
exit

---

6. Router 2 (R2) Configuration

three routers configuration with serial port with static ip configuration with commands 2025

Serial Interface to R1

interface serial0/0/0
ip address 10.0.12.2 255.255.255.252
no shutdown
exit

Serial Interface to R3 (DCE)

interface serial0/0/1
ip address 10.0.23.1 255.255.255.252
clock rate 64000
no shutdown
exit

---

7. Router 3 (R3) Configuration

three routers configuration with serial port with static ip configuration with commands 2025

Configure LAN Interface

interface gigabitEthernet0/0
ip address 192.168.3.1 255.255.255.0
no shutdown
exit

Configure Serial Interface

interface serial0/0/0
ip address 10.0.23.2 255.255.255.252
no shutdown
exit

---

8. Static Routing Configuration

 

three routers configuration with serial port with static ip configuration with commands 2025

Since we are using static IP routing, each router must know how to reach other networks.

---

Static Routes on Router 1

ip route 192.168.3.0 255.255.255.0 10.0.12.2

---

Static Routes on Router 2

ip route 192.168.1.0 255.255.255.0 10.0.12.1
ip route 192.168.3.0 255.255.255.0 10.0.23.2

---

Static Routes on Router 3

ip route 192.168.1.0 255.255.255.0 10.0.23.1

---

9. PC Configuration

three routers configuration with serial port with static ip configuration with commands 2025

PC1

• IP: 192.168.1.2
• Subnet Mask: 255.255.255.0
• Default Gateway: 192.168.1.1

PC2

• IP: 192.168.3.2
• Subnet Mask: 255.255.255.0
• Default Gateway: 192.168.3.1

---

10. Verification Commands

three routers configuration with serial port with static ip configuration with commands 2025

Check Interface Status

show ip interface brief

Check Routing Table

show ip route

Test Connectivity

ping 192.168.3.2
traceroute 192.168.3.2

---

11. Common Troubleshooting

 

three routers configuration with serial port with static ip configuration with commands 2025

• Interface down → no shutdown
• Wrong IP → check subnet
• No ping → check static routes
• Serial link down → verify clock rate

---

12. Advantages of Static Routing

three routers configuration with serial port with static ip configuration with commands 2025

• Simple
• Secure
• Low overhead
• Best for small networks

---

13. Disadvantages

three routers configuration with serial port with static ip configuration with commands 2025

• Manual configuration
• Not scalable
• No automatic failover

---

14. Use Cases

three routers configuration with serial port with static ip configuration with commands 2025

• CCNA labs
• Interview demonstrations
• Small office WAN
• Educational purpose

---

15. Conclusion

three routers configuration with serial port with static ip configuration with commands 2025

This guide demonstrated three-router configuration using serial ports with static IP addressing in a clear, real‑world method. By following these steps, you can successfully build and troubleshoot WAN topologies in 2025 networking environments.

---

🔹 Need Next?

• ACL configuration on 3 routers
• RIP / OSPF dynamic routing
• Packet Tracer file
•  

Just tell me 👍

video link to click here

example 2

static ip address configuration three routers with serial cable

 

router0
========

router>en

router#config t

router(config)#hostname r0

r0(config)#interface f0/0

r0(config-if)#ip add 10.0.0.1 255.0.0.0

r0(config-if)#no shutdown

r0(config-if)#exit

r0(config)#interface s1/0

ro(config-if)#ip add 20.0.0.1 255.0.0.0

r0(config-if)#clock rate 64000

r0(config-if)#no shutdown

r0(config-if)#exit

r0(config)#

routing part
=============
R0
Router(config)#ip route 30.0.0.0 255.0.0.0 20.0.0.2
Router(config)#ip route 40.0.0.0 255.0.0.0 20.0.0.2
Router(config)#ip route 50.0.0.0 255.0.0.0 20.0.0.2

 

 

 

router1
================

router>en

router#config t

router(config)#hostname r1

r1(config)#interface f0/0

r1(config-if)#ip add 20.0.0.1 255.0.0.0

r1(config-if)#no shutdown

r1(config-if)#exit

r1(config)#interface s1/0

r1(config-if)#ip add 20.0.0.2 255.0.0.0

r1(config)#interface s1/1

r1(config-if)#ip add 40.0.0.2 255.0.0.0

r1(config-if)#no shutdown

r1(config-if)#exit

r1(config)#

routing part
=============

r1(config-if)#no shutdown

r1(config-if)#exit

r1(config)#

routing part
=============
R1
Router(config)#ip route 10.0.0.0 255.0.0.0 20.0.0.1
Router(config)#ip route 50.0.0.0 255.0.0.0 40.0.0.2

 

router2
================

router>en

router#config t

router(config)#hostname r2

r2(config)#interface f0/0

r2(config-if)#ip add 20.0.0.1 255.0.0.0

r2(config-if)#no shutdown

r2(config-if)#exit

r2(config)#interface s1/0

r2(config-if)#ip add 40.0.0.2 255.0.0.0

r2(config-if)#no shutdown

r2(config-if)#exit

r2(config)#

routing part
=============
R2
Router(config)#ip route 10.0.0.0 255.0.0.0 40.0.0.1
Router(config)#ip route 20.0.0.0 255.0.0.0 40.0.0.1
Router(config)#ip route 30.0.0.0 255.0.0.0 40.0.0.1

 

 

 

switch configuration

cisco 2950 switch configuration

sw 0

Switch>en
Switch#vlan database
Switch(vlan)#vlan 10 name admin
Switch(vlan)#vlan 20 name mark
Switch#sh vlan
Switch#conf t
Switch(config)#int f0/1
Switch(config-if)#switchport access vlan 10
Switch(config-if)#int f0/2
Switch#exit

sw 1
Switch>en
Switch#vlan database
Switch(vlan)#vlan 10 name hr
Switch(vlan)#vlan 20 name agents
Switch#sh vlan
Switch#conf t
Switch(config)#int f0/1
Switch(config-if)#switchport access vlan 10
Switch(config-if)#int f0/2
Switch#exit