Certain problems appear repeatedly. Learn to recognize their symptoms and you will solve issues faster.
Complete loss of connectivity:
- Check physical layer first
- Verify IP configuration
- Test default gateway reachability
Intermittent connectivity:
- Duplex mismatch causing collisions
- Flapping interface going up and down
- DNS issues making some sites fail
Slow performance:
- Bandwidth saturation
- High latency on WAN links
- MTU issues causing fragmentation
Document the symptoms precisely. Intermittent issues need more investigation than complete failures.