tracert / traceroute Command

Nerd Cafe | نرد کافه

1. Topology Overview

2. IP Addressing Plan

Device	Interface	IP Address	Subnet Mask
PC1	NIC	192.168.1.100	255.255.255.0
R1	fa0/0	192.168.1.1	255.255.255.0
R1	s0/0/0	10.0.0.1	255.255.255.252
R2	s0/0/0	10.0.0.2	255.255.255.252
R2	s0/1/0	10.0.0.5	255.255.255.252
R3	s0/1/0	10.0.0.6	255.255.255.252
R3	fa0/0	192.168.3.1	255.255.255.0
PC2	NIC	192.168.3.100	255.255.255.0

• Switches are Layer 2 only, so no IP addresses needed.

3. Configure PCs

PC1

IP: 192.168.1.100
Subnet: 255.255.255.0
Default Gateway: 192.168.1.1

PC2

IP: 192.168.3.100
Subnet: 255.255.255.0
Default Gateway: 192.168.3.1

4. Configure Routers with EIGRP

R1

Router>enable 
Router#configure terminal 
Router(config)#hostname R1
R1(config)#interface fastEthernet 0/0
R1(config-if)#ip address 192.168.1.1 255.255.255.0
R1(config-if)#no shutdown 
R1(config-if)#exit
R1(config)#interface s0/0/0
R1(config-if)#ip address 10.0.0.1 255.255.255.252
R1(config-if)#no shutdown 
R1(config-if)#exit
R1(config)#router eigrp 100
R1(config-router)#network 192.168.1.0 0.0.0.255
R1(config-router)#network 10.0.0.0 0.0.0.3
R1(config-router)#no auto-summary 
R1(config-router)#^Z
R1#write memory 
Building configuration...
[OK]
R1#

R2

Router>enable 
Router#configure terminal
Router(config)#hostname R2
R2(config)#interface serial 0/0/0
R2(config-if)#ip address 10.0.0.2 255.255.255.252
R2(config-if)#no shutdown 
R2(config-if)#exit
R2(config)#interface serial 0/1/0
R2(config-if)#ip address 10.0.0.5 255.255.255.252
R2(config-if)#no shutdown 
R2(config-if)#exit 
R2(config)#router eigrp 100
R2(config-router)#network 10.0.0.0 0.0.0.3
R2(config-router)#network 10.0.0.4 0.0.0.3
R2(config-router)#no auto-summary 
R2(config-router)#^Z
R2#write memory 
Building configuration...
[OK]
R2#

R3

Router>enable 
Router#configure terminal 
Router(config)#interface serial 0/1/0
Router(config-if)#ip add
Router(config-if)#ip address 10.0.0.6 255.255.255.252
Router(config-if)#no shutdown 
Router(config-if)#exit
Router(config)#interface fastEthernet 0/0
Router(config-if)#ip address 192.168.3.1 255.255.255.0
Router(config-if)#no shutdown 
Router(config-if)#exit
Router(config)#router eigrp 100
Router(config-router)#network 10.0.0.4 0.0.0.3
Router(config-router)#network 192.168.3.0 0.0.0.255
Router(config-router)#no auto-summary 
Router(config-router)#
Router(config-router)#^Z
Router#write memory 
Building configuration...
[OK]
Router#

5. Verify Routing

R1

R1#show ip route 
Codes: C - connected, S - static, I - IGRP, 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, E - EGP
       i - IS-IS, 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

Gateway of last resort is not set

     10.0.0.0/30 is subnetted, 2 subnets
C       10.0.0.0 is directly connected, Serial0/0/0
D       10.0.0.4 [90/21024000] via 10.0.0.2, 00:04:17, Serial0/0/0
C    192.168.1.0/24 is directly connected, FastEthernet0/0
D    192.168.3.0/24 [90/21026560] via 10.0.0.2, 00:03:25, Serial0/0/0
R1#

R2

R2#show ip route 
Codes: C - connected, S - static, I - IGRP, 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, E - EGP
       i - IS-IS, 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

Gateway of last resort is not set

     10.0.0.0/30 is subnetted, 2 subnets
C       10.0.0.0 is directly connected, Serial0/0/0
C       10.0.0.4 is directly connected, Serial0/1/0
D    192.168.1.0/24 [90/20514560] via 10.0.0.1, 00:08:09, Serial0/0/0
D    192.168.3.0/24 [90/20514560] via 10.0.0.6, 00:04:10, Serial0/1/0
R2#

R3

R3#show ip route 
Codes: C - connected, S - static, I - IGRP, 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, E - EGP
       i - IS-IS, 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

Gateway of last resort is not set

     10.0.0.0/30 is subnetted, 2 subnets
D       10.0.0.0 [90/21024000] via 10.0.0.5, 00:05:45, Serial0/1/0
C       10.0.0.4 is directly connected, Serial0/1/0
D    192.168.1.0/24 [90/21026560] via 10.0.0.5, 00:05:45, Serial0/1/0
C    192.168.3.0/24 is directly connected, FastEthernet0/0
R3#

6. Verify Connectivity

From PC1:

PC>ping 192.168.3.100

Pinging 192.168.3.100 with 32 bytes of data:

Reply from 192.168.3.100: bytes=32 time=3ms TTL=125
Reply from 192.168.3.100: bytes=32 time=2ms TTL=125
Reply from 192.168.3.100: bytes=32 time=2ms TTL=125
Reply from 192.168.3.100: bytes=32 time=2ms TTL=125

Ping statistics for 192.168.3.100:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 2ms, Maximum = 3ms, Average = 2ms

PC>

7. Understanding tracert / traceroute

Purpose

• Shows the path packets take from source to destination.

• Measures round-trip time (RTT) per hop.

• Identifies routing issues or slow links.

How it Works

1. tracert sends ICMP Echo Requests with TTL=1.

2. Each router decrements TTL by 1.

3. When TTL = 0 → router sends ICMP Time Exceeded.

4. tracert prints router IP and RTT.

5. TTL increments until reaching the destination.

Expected Output

PC>tracert 192.168.3.100

Tracing route to 192.168.3.100 over a maximum of 30 hops: 

  1   1 ms      0 ms      0 ms      192.168.1.1
  2   1 ms      1 ms      0 ms      10.0.0.2
  3   1 ms      2 ms      0 ms      10.0.0.6
  4   1 ms      1 ms      1 ms      192.168.3.100

Trace complete.

PC>

Cisco Packet Tracer (Version 6.2.0.0052)

70KB

tracert-command.pkt

Open

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Keywords

TTL, ICMP, hops, round-trip-time, latency, router, path, diagnostic, packet, time-exceeded, echo-request, echo-reply, network-troubleshooting, route-discovery, IP-address, gateway, delay, forwarding, connectivity, troubleshooting, Nerd Cafe , نرد کافه

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