To use the traceroute command in a network
simulation tool (such as Cisco Packet Tracer), follow this structured
approach.
1. Purpose of
Traceroute
Traceroute is used to:
- Identify the path packets take from source
to destination
- Detect where delays or packet drops occur
- Verify routing and gateway configuration in
a simulated network
2. Using Traceroute
in Cisco Packet Tracer (PC)
Step-by-step:
1.
Click on a PC
in the topology
2.
Select Desktop
3.
Open Command
Prompt
4.
Enter:
tracert 8.8.8.8
or
tracert www.example.com
Each line in the output represents a router hop.
3. Using Traceroute
on a Router (Cisco IOS)
1.
Click the Router
2.
Go to the CLI
3.
Type:
traceroute 8.8.8.8
This traces the route directly from the router
itself.
4. Interpreting the
Output
- Hop number:
Sequence of routers
- IP address:
Interface responding at that hop
- Time (ms):
Latency to that hop
- * * *:
No response (ICMP blocked, ACL issue, or misconfiguration)
5. Common
Simulation Issues & Fixes
| Issue | Likely Cause | Fix |
|---|---|---|
| Trace fails immediately | No default gateway | Configure the correct default gateway on the PC |
| Name does not resolve | DNS not configured | Use the destination IP address instead of a domain name |
| Traceroute stops at a router | ACL blocking ICMP | Review and modify Access Control Lists |
| High response time | Network congestion | Check bandwidth usage and interface status |
| No reply from all hops | Routing misconfiguration | Verify routing tables and static or dynamic routes |
6. Best Practice in
Simulations
- Always ping first before traceroute
- Use IP addresses to avoid DNS dependency
- Verify routing tables with:
show ip route
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