1.4 7 Packet Tracer Configure Router Interfaces: Exact Answer & Steps

You've stared at the Packet Tracer window for twenty minutes. Still, the topology looks simple enough — two routers, a switch, a couple of PCs. But every time you try to ping across the link, you get "Destination Host Unreachable" or "Request Timed Out.

Sound familiar?

Here's the thing: Lab 1.7 isn't testing your ability to memorize commands. 4.It's testing whether you actually understand what an interface does when you bring it up. In real terms, most students rush through the IP addressing part and skip the verification steps. That's where the points disappear — and where real troubleshooting skills are born Not complicated — just consistent..

Let's walk through it properly.

What Is Lab 1.4.7 Anyway

This is the classic "Configure Router Interfaces" lab from the Cisco Networking Academy CCNA curriculum. Module 1, Topic 4, Lab 7. You're given a pre-built topology: two routers connected via a serial link (or sometimes GigabitEthernet, depending on the Packet Tracer version), each with a LAN hanging off it. Your job — assign IP addresses, enable the interfaces, verify connectivity, and document the whole thing Practical, not theoretical..

Real talk — this step gets skipped all the time.

Simple on paper. Worth adding: in practice? This is where you learn that no shutdown isn't optional, that clock rate matters on DCE serial links, and that show ip interface brief tells you more than show running-config ever will.

The Topology You're Working With

Typical setup:

• R1 — G0/0 (LAN side), S0/0/0 (WAN side)
• R2 — G0/0 (LAN side), S0/0/1 (WAN side)
• Switches — one per LAN, connecting PCs
• PCs — pre-configured with IPs and default gateways (usually)

The serial link between routers is the trap. Forget it, and the line protocol stays down. One side is DCE. That's why that side needs a clock rate. Forever Less friction, more output..

Why This Lab Actually Matters

You're not here to pass a checkbox. You're here because interface configuration is the foundation of everything in routing. VLANs, OSPF, BGP, VPNs — none of it works if the interface isn't up/up.

This lab teaches three habits that separate junior admins from seniors:

1. Practically speaking, Read the output — show interfaces speaks. Plan before you type — write down your addressing scheme first
2. Verify every step — don't assume no shutdown worked
3. Listen to it.

Real talk — this step gets skipped all the time Simple, but easy to overlook..

Employers ask about this stuff in interviews. So " If you say "I type the IP and no shutdown," you're not getting the job. Practically speaking, "Walk me through bringing up a serial link. If you say "I check DCE/DTE, set clock rate, verify line protocol, then test end-to-end," you're in the conversation.

Not obvious, but once you see it — you'll see it everywhere.

How to Configure Router Interfaces — Step by Step

1. Examine the Topology and Addressing Table

Before you touch the CLI, open the lab instructions. Find the addressing table. It usually looks something like this:

Write this down. On paper. Or in a text file. Don't rely on the Packet Tracer instruction window — it disappears when you click into the CLI.

2. Access the CLI and Enter Global Config

Click R1. Which means cLI tab. Press Enter to wake it up.

Router> enable
Router# configure terminal
Router(config)#

Same for R2. Practically speaking, open a second CLI window if your screen allows it. Side-by-side saves constant tab-switching Worth knowing..

3. Configure the LAN Interfaces First

Start with the GigabitEthernet interfaces. They're easier — no clock rate drama Not complicated — just consistent..

On R1:

Router(config)# interface g0/0
Router(config-if)# ip address 192.168.1.1 255.255.255.0
Router(config-if)# no shutdown
Router(config-if)# description LAN-to-Switch1
Router(config-if)# exit

On R2:

Router(config)# interface g0/0
Router(config-if)# ip address 192.168.2.1 255.255.255.0
Router(config-if)# no shutdown
Router(config-if)# description LAN-to-Switch2
Router(config-if)# exit

Add descriptions. Now, always. Future-you will thank present-you at 2 AM when something breaks.

4. Configure the Serial Link — This Is Where It Breaks

Now the WAN interfaces. Pay attention.

On R1 (assume S0/0/0 is DCE — check with show controllers):

Router(config)# interface s0/0/0
Router(config-if)# ip address 10.1.1.1 255.255.255.252
Router(config-if)# clock rate 64000
Router(config-if)# no shutdown
Router(config-if)# description WAN-to-R2
Router(config-if)# exit

On R2 (S0/0/1 is DTE):

Router(config)# interface s0/0/1
Router(config-if)# ip address 10.1.1.2 255.255.255.252
Router(config-if)# no shutdown
Router(config-if)# description WAN-to-R1
Router(config-if)# exit

Critical note: The clock rate command only goes on the DCE side. How do you know which side is DCE? In Packet Tracer, hover over the serial cable. It shows a little clock icon on the DCE end. Or run show controllers s0/0/0 — look for "DCE" in the output.

No clock rate = line protocol down. Every time.

5. Verify — Don't Just Assume

This is the step everyone skips. Don't.

Check interface status:

R1# show ip interface brief
Interface              IP-Address      OK? Method Status                Protocol
GigabitEthernet0/0     192.168.1.1     YES manual up                    up
Serial0/0/0            10.1.1.1        YES manual up                    up

Check the routing table:

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, p - overrides from PfR

Gateway of last resort is not set

      10.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C        10.1.1.0/30 is directly connected, Serial0/0/0
L        10.1.1.1/32 is directly connected, Serial0/0/0
      192.168.1.0/24 is variably subnetted, 2 subnets, 2 masks
C        192.168.1.0/24 is directly connected, GigabitEthernet0/0
L        192.168.1.1/32 is directly connected, GigabitEthernet0/0

Notice what's missing? 168.Think about it: same problem on R2 — it doesn't know 192. In practice, the 192. 1.0 network. 168.Day to day, r1 has no idea it exists. 2.Here's the thing — 0. Connected routes only know directly attached networks Took long enough..

6. Configure Static Routes

Since this is a two-router topology, static routing is clean, deterministic, and required for the lab.

On R1 (route to R2's LAN via the serial link):

Router(config)# ip route 192.168.2.0 255.255.255.0 10.1.1.2

Next-hop method. Clean. Uses R2's serial IP.

On R2 (route to R1's LAN):

Router(config)# ip route 192.168.1.0 255.255.255.0 10.1.1.1

Alternative — exit interface method (works on point-to-point serial links):

R1(config)# ip route 192.168.2.0 255.255.255.0 s0/0/0
R2(config)# ip route 192.168.1.0 255.255.255.0 s0/0/1

Both work. Next-hop is more explicit; exit-interface saves a recursive lookup. Pick one and stay consistent.

7. Verify the Routes Installed

R1# show ip route
...
S     192.168.2.0/24 [1/0] via 10.1.1.2

The S means static. [1/0] is administrative distance 1, metric 0. It's in the table. Good And it works..

Do the same on R2. Confirm 192.168.1.0/24 appears.

8. Test End-to-End Connectivity

Go to PC1. Open Command Prompt.

PC> ping 192.168.2.10

First ping might fail — ARP resolution. Second should succeed That's the part that actually makes a difference..

Pinging 192.168.2.10 with 32 bytes of data:
Reply from 192.168.2.10: bytes=32 time=12ms TTL=126
Reply from 192.168.2.10: bytes=32 time=8ms TTL=126
Reply from 192.168.2.10: bytes=32 time=10ms TTL=126
Reply from 192.168.2.10: bytes=32 time=9ms TTL=126

Ping statistics for 192.Think about it: 168. 2.