Lab ID: PTL-0022
Title: DNS Records and HTTP Web Services
Status: TESTED_PASS (Verified live in Cisco Packet Tracer 9.0.1 via MCP loopback bridge automation)
1. Packet Tracer Topology Construction Manifest#
To construct or manually verify this topology in Cisco Packet Tracer:
Device Inventory#
| Device Role | PT Device Model | Display Name | Modules / Slots |
|---|---|---|---|
| Default Gateway Router | Cisco ISR 4321 | R1 | Default GigabitEthernet0/0/0 & GigabitEthernet0/0/1 |
| Client Access Switch | Cisco Catalyst 2960-24TT | S1 | 24 FastEthernet + 2 GigabitEthernet ports |
| Server Farm Access Switch | Cisco Catalyst 2960-24TT | S2 | 24 FastEthernet + 2 GigabitEthernet ports |
| Client Workstation 1 | PC-PT | PC-1 | FastEthernet0 |
| Client Workstation 2 | PC-PT | PC-2 | FastEthernet0 |
| Authoritative DNS Server | Server-PT | DNS-Server | FastEthernet0 |
| Corporate Web Portal Server | Server-PT | Web-Server | FastEthernet0 |
Physical Cabling Matrix#
| Link ID | Source Device | Source Port | Destination Device | Destination Port | Cable Type |
|---|---|---|---|---|---|
| L-01 | PC-1 | FastEthernet0 | S1 | FastEthernet0/1 | Copper Straight-Through |
| L-02 | PC-2 | FastEthernet0 | S1 | FastEthernet0/2 | Copper Straight-Through |
| L-03 | S1 | GigabitEthernet0/1 | R1 | GigabitEthernet0/0/0 | Copper Straight-Through |
| L-04 | R1 | GigabitEthernet0/0/1 | S2 | GigabitEthernet0/1 | Copper Straight-Through |
| L-05 | S2 | FastEthernet0/10 | DNS-Server | FastEthernet0 | Copper Straight-Through |
| L-06 | S2 | FastEthernet0/11 | Web-Server | FastEthernet0 | Copper Straight-Through |
2. Positive Verification Test Matrix#
| Test ID | Objective | Command / Procedure | Expected Result | Pass Criteria |
|---|---|---|---|---|
| POS-01 | Subnet Routing | PC-1> ping 192.168.20.80 |
3/3 echo replies from Web-Server with TTL=127 across router R1 |
IP routing verified between subnets |
| POS-02 | Primary A Record Lookup | PC-1> nslookup web.corp.local |
Query returns Address: 192.168.20.80 from server 192.168.20.50 |
Primary FQDN resolves to server IPv4 address |
| POS-03 | CNAME Canonical Alias | PC-1> nslookup www.corp.local |
Query returns Aliases: web.corp.local and Address: 192.168.20.80 |
Alias resolves to canonical target A record |
| POS-04 | Secondary A Record Lookup | PC-2> nslookup portal.corp.local |
Query returns Address: 192.168.20.80 from server 192.168.20.50 |
Second host query resolves successfully |
| POS-05 | HTTP Web Page Delivery | PC-1 Web Browser> URL: http://www.corp.local |
Browser renders "Corporate Intranet Portal" page | Web client loads page using resolved hostname |
3. Negative & Fault Tolerance Test Matrix#
| Test ID | Fault Scenario | Injection Procedure | Observed Symptom | Recovery Procedure |
|---|---|---|---|---|
| NEG-01 | Non-Existent Domain Query | On PC-1:nslookup nonexistent.corp.local |
Server returns *** UnKnown can't find nonexistent.corp.local: Non-existent domain.. |
Expected response: DNS server refuses resolution of unmapped hostnames. |
| NEG-02 | DNS Record Removal & Recovery | On DNS-Server: Remove A record portal.corp.localOn PC-2: nslookup portal.corp.local |
Query fails with Non-existent domain. |
On DNS-Server, restore A record portal.corp.local pointing to 192.168.20.80. Re-run nslookup on PC-2 and verify immediate success. |
4. Save and Persistence Verification Check#
- On R1, S1, and S2, execute
copy running-config startup-config. - Save the completed topology file (
completed.pkt). - Reload
completed.pktin Cisco Packet Tracer. - Execute
nslookup web.corp.localonPC-1and confirm DNS service and database records persist across reloads. - Reload
starter.pktand confirm that with DNS disabled, queries toweb.corp.localfail as expected, confirming clear differentiation between starter and solution files.