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Troubleshooting Tools
Metodologi Scenario Issues Diagnosis Tools Template Log

Pertemuan 7: Review & Integrated Troubleshooting 1

Progress Pembelajaran 7/16
Persiapan UTS

Pertemuan ini merupakan persiapan untuk Ujian Tengah Semester. Fokus pada kemampuan troubleshooting integrasi dasar jaringan enterprise.

Tujuan Pembelajaran

Mahasiswa mampu mendiagnosis dan memperbaiki skenario jaringan yang sengaja dikonfigurasi salah menggunakan metodologi troubleshooting yang sistematis.

Metodologi Troubleshooting Sistematis

1. Pendekatan Layer OSI

Troubleshooting yang efektif mengikuti model OSI layer dari bawah ke atas (Bottom-Up):

Bottom-Up Approach
  1. Layer 1 - Physical: Kabel, konektor, power
  2. Layer 2 - Data Link: MAC address, VLAN, STP
  3. Layer 3 - Network: IP addressing, routing
  4. Layer 4-7 - Upper Layers: Services, applications
Divide and Conquer
  1. Problem Identification: Gejala yang diamati
  2. Information Gathering: Collect data dan evidence
  3. Hypothesis: Dugaan penyebab masalah
  4. Testing: Verifikasi hypothesis
  5. Solution: Implementasi perbaikan
  6. Verification: Konfirmasi masalah teratasi
2. Systematic Troubleshooting Methodology
1
Problem Report

Identifikasi gejala dan scope masalah

→
2
Information Gathering

Kumpulkan data dengan show commands

→
3
Hypothesis

Buat dugaan berdasarkan evidence

→
4
Testing

Test hypothesis dengan targeted commands

→
5
Solution

Implementasi fix yang tepat

→
6
Verification

Konfirmasi masalah teratasi

3. Common Issues Matrix
Layer Common Issues Diagnosis Commands Solution Approach
Physical Kabel rusak, port down, power issue show interfaces, show ip interface brief Ganti kabel, reset port, cek power
Data Link VLAN mismatch, STP loops, Duplex mismatch show vlan, show spanning-tree, show interfaces Fix VLAN config, STP tuning, set duplex
Network IP conflict, Routing issues, ACL blocking show ip route, show ip ospf neighbor, show access-lists Fix IP scheme, routing config, ACL rules
Application Service down, Port blocked, DNS issues telnet, ping, traceroute, nslookup Restart service, open ports, fix DNS

Troubleshooting Challenge

Informasi Troubleshooting Challenge

Durasi: 170 menit

Topik: Integrated Troubleshooting

Format: Team-based challenge

Tujuan: Diagnosis multi-layer issues

Tools: Cisco Packet Tracer + Pre-configured issues

Penilaian: Systematic methodology

Scenario Overview
Problem Statement:

"Anda sebagai network engineer diminta memperbaiki jaringan enterprise yang mengalami multiple issues. Hasil initial test menunjukkan:"

  • PC1 bisa ping PC2 ✓
  • PC1 tidak bisa ping PC3 ✗
  • PC1 tidak bisa ping PC4 ✗
  • Router1 tidak melihat route ke 192.168.30.0/24 ✗
  • OSPF adjacency stuck di INIT ✗
Hidden Issues (Disediakan Instruktur)
Daftar Issues yang Disembunyikan:
Layer 2 Issues
  • VLAN Mismatch: VLAN database tidak konsisten
  • Trunk Configuration Error: Port trunk salah konfigurasi
  • STP Issues: Loop prevention tidak aktif
  • VTP Domain Mismatch: VLAN tidak terdistribusi
Layer 3 Issues
  • OSPF Area Mismatch: Router di area yang salah
  • Network Statements Missing: Jaringan tidak diiklankan
  • IP Addressing Conflicts: Duplicate IP addresses
  • ACL Blocking: ACL terlalu restriktif
Troubleshooting Tools & Commands
Phase 1: Information Gathering
Physical & Data Link Layer:
! Physical connectivity check
show ip interface brief
show interfaces status
show cdp neighbors

! VLAN dan Trunking verification
show vlan brief
show interfaces trunk
show vtp status
show spanning-tree summary
Network Layer:
! IP Addressing dan Routing check
show ip route
show ip route ospf
show ip ospf neighbor
show ip ospf interface brief

! OSPF Specific troubleshooting
show ip ospf database
debug ip ospf events
show running-config | section router ospf
Phase 2: Targeted Diagnosis
Connectivity Testing:
! End-to-End connectivity test
! Dari PC test konektivitas bertahap
ping gateway_local
ping gateway_remote
ping PC_lain_seVLAN
ping PC_lain_bedaVLAN
traceroute destination_ip
Advanced Diagnostics:
! Debug commands (gunakan dengan hati-hati)
debug ip packet
debug ip ospf adj
debug ppp authentication

! Packet Tracer Simulation Mode
! Gunakan simulation mode untuk melihat packet flow
Troubleshooting Scenarios
Scenario 1: Inter-VLAN Routing Failure

Symptoms: PC1 bisa ping PC2 tapi tidak bisa ping PC3

Expected Resolution: Perbaiki OSPF area configuration dan network statements

Diagnosis Steps:

  1. Verifikasi VLAN assignment pada kedua switch
  2. Check trunk configuration antara switch
  3. Verifikasi OSPF neighbor adjacency
  4. Check network statements di OSPF configuration
Key Commands:
show vlan brief
show interfaces trunk
show ip ospf neighbor
show ip route ospf
Scenario 2: OSPF Routing Issues

Symptoms: Router tidak belajar route dari router lain, OSPF adjacency stuck di INIT

Expected Resolution: Perbaiki OSPF configuration dan area assignment

Diagnosis Steps:

  1. Verifikasi OSPF neighbor adjacency status
  2. Check network statements dan wildcard masks
  3. Periksa area assignment consistency
  4. Verifikasi interface OSPF status dan authentication
Key Commands:
show ip ospf neighbor
show ip ospf interface
debug ip ospf events
show running-config | section ospf
Scenario 3: Security Policy Violation

Symptoms: HTTP traffic diblokir padahal seharusnya diizinkan

Expected Resolution: Perbaiki extended ACL configuration

Diagnosis Steps:

  1. Check applied ACLs pada interfaces
  2. Verifikasi ACL rules dan order
  3. Test traffic dengan different protocols
  4. Monitor ACL hit counts
Key Commands:
show access-lists
show ip interface
debug ip packet
show running-config | include access-list

Troubleshooting Log Template

Template Troubleshooting Log - [Nama Kelompok]
### Issue 1: [Deskripsi Masalah]
Symptoms: [Gejala yang diamati - detail dan spesifik]
Hypothesis: [Dugaan penyebab berdasarkan evidence]
Testing: [Command dan testing yang dilakukan]
Findings: [Hasil investigation dan root cause]
Solution: [Konfigurasi perbaikan yang diimplementasikan]
Verification: [Proof perbaikan berhasil - screenshot/output]
Tips Documentation:
  • Gunakan timestamp untuk setiap entry
  • Document sebelum/sesudah configuration
  • Sertakan screenshot verification commands
  • Catat waktu yang dibutuhkan untuk setiap issue

Troubleshooting Best Practices

Do's
  • Gunakan systematic methodology
  • Document setiap step troubleshooting
  • Test perubahan sebelum lanjut ke issue berikutnya
  • Work sebagai team dengan role yang jelas
  • Verify final result dengan comprehensive testing
Don'ts
  • Jangan buat multiple changes simultaneously
  • Jangan skip documentation
  • Jangan ignore basic checks
  • Jangan panic ketika ada issues
  • Jangan lupa test incrementally
Time Management Strategy:
Phase 1 (30 menit):
Information gathering dan baseline testing
Phase 2 (90 menit):
Targeted diagnosis dan solution implementation
Phase 3 (50 menit):
Verification dan documentation

Success Metrics

Metric Target Measurement Weight
Issue Identification 100% issues teridentifikasi Completeness of problem list 40%
Solution Accuracy 100% solutions correct Appropriateness of fixes 30%
Methodology Systematic approach Structured troubleshooting process 20%
Documentation Complete and clear Quality of troubleshooting log 10%
Pertemuan 6 UTS