Many users report guest network instability (dropped connections, no DHCP, no internet). Below are verified fixes.
| Issue | Symptom | Root Cause | Fixed Solution |
|-------|---------|------------|--------------------|
| No IP assigned | Devices stuck on “Obtaining IP address” | DHCP server for guest network crashes or conflicts with main DHCP range. | Static IP Range: Set Guest DHCP range outside main pool.
Main: 192.168.31.100–200
Guest: 192.168.33.50–150 (different subnet) |
| Guest sees main LAN devices | Security breach | AP isolation disabled or incorrect VLAN tagging. | Enable AP Isolation: In Guest Wi-Fi settings, check “Allow guests to access each other” → NO.
“Allow guests to access local network” → NO. |
| Slow / intermittent speed | High latency, packet loss | Co-channel interference with main 2.4 GHz network. | Fixed Channel: Set main Wi-Fi to channel 1,6,11 (e.g., ch6). Set Guest Wi-Fi to same channel (AX1800 forces same radio). Reduce beacon interval to 100ms. |
| Clients disconnect every 30 min | Logout loop | Default DHCP lease time too short (2 hours). | Increase Lease Time: Via SSH or config file → Set dhcp_lease_time=86400 (24 hours). Not exposed in GUI – requires advanced access. |
| No internet for guests | DNS failure | Router’s DNS proxy doesn’t forward guest subnet. | Manual DNS: In Guest settings, set Primary DNS 8.8.8.8, Secondary 1.1.1.1. Disable “Use same DNS as main network”. | create guest network on xiaomi mi router ax1800 fixed
The Fix:
The Mi Wi-Fi app is often simplified. Always use the web interface (192.168.31.1) for guest network isolation settings. The app may hide the “Access Intranet” toggle, leaving your network exposed. | Static IP Range: Set Guest DHCP range outside main pool
After applying the fixes above, use these "golden configuration" settings for the Xiaomi Mi Router AX1800 to ensure zero future dropouts. “Allow guests to access local network” → NO
| Setting | Recommended Value | Why? |
| :--- | :--- | :--- |
| SSID | YourName_Guest | Do not hide SSID (hidden networks cause reconnection failures on Xiaomi) |
| Band | 2.4 GHz Only | Avoids the 5GHz driver crash bug on AX1800 |
| Security | WPA2-PSK | WPA3 on guest network breaks many legacy client devices |
| Guest DNS | 8.8.8.8 / 1.1.1.1 | Bypasses the router’s internal DNS cache bug |
| Speed Limit | 10 Mbps up/down | Prevents guests from saturating your 1Gbps fiber line |
| Access Local | OFF | Security (Turn ON only if you have a guest printer) |
| Access Each Other | OFF | Prevents infected guest devices from spreading malware |
| Validity | No expiry | If you set a time limit, the AX1800 sometimes fails to auto-renew |