Traceroute Test

Nerd Cafe

Step 1: Understanding traceroute (Linux/macOS) & tracert (Windows)

• Purpose:

  • Helps track the path a packet takes from source to destination.

  • Identifies where network delays or failures occur.

• Commands:

  • Windows: tracert [destination IP]

  • Linux/macOS: traceroute [destination IP]

Step 2: Network Setup with Static Routes

Assuming static routing is already configured, verify your routes:

Topology

Router R1:

R1(config)# ip route 192.168.3.0 255.255.255.0 10.0.0.2

• This route tells R1 that to reach 192.168.3.0/24, forward packets to R2 (10.0.0.2).

Router R2:

R2(config)# ip route 192.168.3.0 255.255.255.0 10.0.1.2
R2(config)# ip route 192.168.1.0 255.255.255.0 10.0.0.1

• First route: To reach 192.168.3.0/24, forward packets to R3 (10.0.1.2).

• Second route: To reach 192.168.1.0/24, forward packets to R1 (10.0.0.1).

Router R3:

R3(config)# ip route 192.168.1.0 255.255.255.0 10.0.1.1

• This route tells R3 that to reach 192.168.1.0/24, forward packets to R2 (10.0.1.1).

Step 3: Running tracert from PC1 to PC3

PC1>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      1 ms      10.0.0.2
  3   2 ms      22 ms     0 ms      10.0.1.2
  4   1 ms      3 ms      0 ms      192.168.3.100

Trace complete.

PC1>

• Each hop represents a router in the network.

• The times in ms (milliseconds) show response delays.

Step 4: Troubleshooting with tracert

If tracert does not work or times out:

• Verify Static Routes for 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, 1 subnets
C       10.0.0.0 is directly connected, Serial0/0/0
C    192.168.1.0/24 is directly connected, FastEthernet0/0
S    192.168.2.0/24 is directly connected, Serial0/0/0
S    192.168.3.0/24 is directly connected, Serial0/0/0
R1#

• Verify Static Routes for 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       10.0.1.0 is directly connected, Serial0/1/0
S    192.168.1.0/24 is directly connected, Serial0/0/0
C    192.168.2.0/24 is directly connected, FastEthernet0/0
S    192.168.3.0/24 is directly connected, Serial0/1/0
R2#

• Verify Static Routes for 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 0.0.0.0 to network 0.0.0.0

     10.0.0.0/30 is subnetted, 1 subnets
C       10.0.1.0 is directly connected, Serial0/1/0
C    192.168.3.0/24 is directly connected, FastEthernet0/0
S*   0.0.0.0/0 is directly connected, Serial0/1/0
R3#

• Check connectivity using ping:

PC1>ping 192.168.1.1

Pinging 192.168.1.1 with 32 bytes of data:

Reply from 192.168.1.1: bytes=32 time=1ms TTL=255
Reply from 192.168.1.1: bytes=32 time=1ms TTL=255
Reply from 192.168.1.1: bytes=32 time=0ms TTL=255
Reply from 192.168.1.1: bytes=32 time=0ms TTL=255

Ping statistics for 192.168.1.1:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 0ms, Maximum = 1ms, Average = 0ms

PC1>ping 192.168.2.100

Pinging 192.168.2.100 with 32 bytes of data:

Reply from 192.168.2.100: bytes=32 time=14ms TTL=126
Reply from 192.168.2.100: bytes=32 time=1ms TTL=126
Reply from 192.168.2.100: bytes=32 time=2ms TTL=126
Reply from 192.168.2.100: bytes=32 time=1ms TTL=126

Ping statistics for 192.168.2.100:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 1ms, Maximum = 14ms, Average = 4ms

PC1>ping 192.168.3.100

Pinging 192.168.3.100 with 32 bytes of data:

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=16ms 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 = 16ms, Average = 5ms

PC1>

Keywords

Traceroute, Tracert, Static Routing, Network Troubleshooting, ICMP, Hop Count, Packet Path, Latency, Ping, Route Verification, Show IP Route, Show IP Interface Brief, Router Configuration, Network Delay, Packet Switching, Routing Table, Network Connectivity, Path Analysis, Command Prompt, Terminal, نتورک پلاس