UDM Pro SFP+ port cannot link to a UniFi US-24 1G SFP port over an SFP+ DAC
A new UDM Pro replaced a USG-3; plugging its LAN SFP+ port into the free SFP port of a UniFi Switch 24 with a known-good SFP+ DAC (taken from a working switch-to-switch link) gave no link on either UDM Pro port, and manually setting the UDM Pro port to 1 Gbps did not help. Several other users confirmed the same with DACs.
- Hardware: Ubiquiti UDM Pro, Ubiquiti US-24, Ubiquiti US-16-150W
- Transceivers: Ubiquiti SFP+ DAC, 1G fibre SFP modules, OM3 fibre
- Form factor: SFP, SFP+, DAC
Symptoms / messages:
no link between SFP+ DAC and 1G SFP port
manual 1G setting has no effect
Also available in: English
العربية
Deutsch
Español
Français
हिन्दी
Bahasa Indonesia
Italiano
日本語
한국어
Nederlands
Polski
Português
Русский
Türkçe
Tiếng Việt
简体中文
Comments 1
A 10G DAC fails auto-negotiation against a 1G SFP port and the early UDM Pro firmware could not force the SFP+ port to 1G; use 1G fiber modules on both ends (confirmed working over OM3 to a 24-port PoE switch) or a plain 1G SFP cable until a firmware fix.