In my “home-domain” environment there is also my Wingo TV-Box settled. One day I noticed that my TV-Box is giving out an error, that it can’t reach the internet anymore “please check if NTP port 123 is getting blocked in your local network”. Since nothing in the hardware had changed, I began my search on my DHCP server.
The “NTP Port 123” Trap
In many homelab setups, a TV box that cannot reach its home platform will throw a generic “NTP Port 123” or “Check Internet Connection” error. While it looks like a firewall issue, it is often a handshake failure. The box is connected to your local network but doesn’t “trust” the connection because the DHCP server hasn’t provided the necessary vendor-specific credentials.
Essential DHCP Scope Options
For the Wingo TV box to function behind a custom Windows DHCP server, the following Scope Options must be configured:
| Option | Name | Correct Value | Purpose |
| 003 | Router | <IPofWingoRouter> | Must point to the Wingo/Internet Box, not your Windows Server. |
| 006 | DNS Servers | <DC1-IP>,<DC2-IP>,8.8.8.8 | Ensure the box can resolve both internal and public Swisscom hostnames. |
| 042 | NTP Servers | <DC1-IP>,<DC2-IP>, time.google.com | Use a public NTP (like Google) at the top of the list for immediate sync. |
The Secret Sauce – DHCP Option 125
This is the most critical setting. Option 125 (Vendor-Identifying Vendor-Specific Information) acts as a digital passport. Without it, the box remains in a restricted state.
The Magic Hex String:
00 00 0d e9 24 01 06 00 04 00 00 00 01 02 0a 49 50 54 56 5f 53 43 5f 56 32 03 0a 41 44 42 5f 54 4c 43 31 31 30
This string identifies the provider (Swisscom/Wingo) and tells the box it is on a authorized IPTV network.
Troubleshooting the Cluster Hangover
When managing these settings in a Failover Cluster, a crash can lead to “Rogue” DHCP behavior:
- Replicate Failover Scopes: Always ensure your primary and secondary DCs are synchronized. If one node has stale data, the TV box may receive conflicting instructions.
- Authorize the Server: Ensure your Windows DHCP server has a Green Checkmark. If it’s not authorized in AD, it won’t enforce reservations correctly.
- Clear Stale Leases: After changing reservations or Option 125, delete the existing lease in the DHCP console and power-cycle the TV box to force a fresh
DHCP REQUEST.