{"id":154,"date":"2026-07-24T16:02:39","date_gmt":"2026-07-24T14:02:39","guid":{"rendered":"https:\/\/www.lukaswojcik.com\/blog\/?p=154"},"modified":"2026-10-26T12:39:21","modified_gmt":"2026-10-26T11:39:21","slug":"setting-up-backup-internet-with-unifi-ucg-fiber-automatic-switching-after-an-outage","status":"publish","type":"post","link":"https:\/\/www.lukaswojcik.com\/blog\/en\/it-networks\/setting-up-backup-internet-with-unifi-ucg-fiber-automatic-switching-after-an-outage\/","title":{"rendered":"Setting Up Backup Internet with UniFi UCG-Fiber: Automatic Switching After an Outage"},"content":{"rendered":"

Multi-WAN uses more than one internet connection. Failover switches to a backup after a detected fault; load balancing distributes new connections across available links. Neither arrangement guarantees 100% uptime or uninterrupted calls. A common gateway, power supply or cable route can still fail.<\/p>\n

Example: fibre, satellite and mobile backup<\/h2>\n

The example prioritizes Toya fibre, then Starlink, then a ZTE 5G connection. Actual latency, throughput and independence need measurement at the installation site. Starlink reduces dependence on the local access line but still relies on power, a clear view of the sky and the provider network.<\/p>\n

\n\"Fibre,
Conceptual WAN layout. Electrical protection depends on the building and equipment; the drawing is not an installation plan.<\/figcaption><\/figure>\n

Hardware and provider requirements<\/h2>\n

Hardware terms:<\/strong> WAN refers to the internet-facing connection; LAN is the local network. The gateway connects these networks. An ONT terminates the provider’s fibre connection and supplies a usable network connection. An SFP is a pluggable interface module; a matching connector alone does not make it a compatible ONT replacement. PoE carries power and data over Ethernet, and an injector supplies that power to the cable.<\/p>\n

Address translation:<\/strong> NAT translates between local and external IP addresses. CGNAT performs another translation within the provider network, often sharing one public address among several customers. Removing local NAT does not remove that provider layer.<\/p>\n

The UCG-Fiber supports multiple WAN ports; the current specification lists a maximum of six. Three connections therefore require appropriate port assignments and enough remaining LAN connectivity. A fibre subscription does not imply that an arbitrary SFP module can replace the provider ONT: optics, authentication and provider settings must match.<\/p>\n

Bridge mode or IP passthrough can remove an extra local NAT layer, but is not essential for every outbound application. Neither mode creates a public IPv4 address or removes provider-side CGNAT. Incoming services require a separate addressing and firewall design.<\/p>\n