wifi

Band Selection Traps

• 2.4GHz penetrates walls better but congested — neighbors' networks interfere
• 5GHz faster but shorter range — may not reach all rooms
• Same SSID for both bands can cause issues — device may stick to weak 5GHz instead of switching
• 6GHz (WiFi 6E) requires compatible devices — falls back to 5GHz if unsupported

Channel Interference

• 2.4GHz only has 3 non-overlapping channels (1, 6, 11) — using others causes interference with neighbors
• "Auto" channel selection often picks poorly — scan and set manually in congested areas
• 5GHz has more channels but DFS channels may pause for radar — causes brief disconnects near airports
• Microwave ovens interfere with 2.4GHz channel 11 — kitchen dead zones are real

Security Mistakes

• WPA2-Personal minimum — WEP and WPA crackable in minutes
• WPA3 preferred when all devices support — falls back silently if mixed
• WPS is a backdoor — disable it, PIN can be brute-forced regardless of password strength
• Hidden SSID doesn't improve security — devices broadcast it anyway when searching
• MAC filtering trivially bypassed — MACs visible in air, easy to spoof

Speed Issues

• "Connected" doesn't mean good signal — check RSSI, below -70dBm is poor
• WiFi speed is shared medium — many devices = less bandwidth each
• Advertised speeds are theoretical max — real throughput is 50-70% at best
• Old devices slow entire network on 2.4GHz — legacy rates affect everyone
• USB 3.0 devices interfere with 2.4GHz — especially external drives near router

Connection Drops

• DHCP lease expiring causes reconnect — reduce lease time for troubleshooting, increase for stability
• Roaming between access points isn't seamless — same SSID doesn't mean smooth handoff
• Power saving mode causes ping spikes — disable on devices where latency matters
• Driver issues more common than hardware — update or rollback WiFi drivers first

Diagnostics

• Ping router IP, not internet — isolates WiFi from ISP issues
• Signal strength varies by location — walk around while monitoring
• Channel scanner shows neighbor congestion — choose least crowded
• Packet loss under 1% is acceptable — higher indicates interference or range issues

Router Placement

• Center of coverage area, not corner of house — signals radiate outward
• Elevated position improves coverage — floor level gets blocked by furniture
• Away from metal objects and aquariums — water and metal block signals
• Router antennas perpendicular to each other — covers horizontal and vertical planes

Guest Networks

• Isolates untrusted devices from main network — IoT devices can't reach your computers
• Separate password allows sharing without exposing main credentials
• Bandwidth limiting available on most routers — prevent guests from saturating connection
• Captive portal unnecessary for home — just use WPA2 with password

Mesh vs Extenders

• Extenders halve bandwidth — repeating uses same channel for backhaul
• Mesh systems with dedicated backhaul avoid this — wired backhaul even better
• Single router often enough — try repositioning before buying mesh
• Adding access points to wrong locations creates more problems — coverage overlap causes roaming issues