Latest questions from the community.
After a complete power loss a Dell R740 with a four-port Broadcom NDC (2x SFP+, 2x 1GbE) booted normally but the fibre SFP+ modules stayed unpowered and disconnected; a reboot did not help and only physically removing and reinserting the modules restored them. Dell support pointed at drivers and…
A UCG-Fiber used a UACC-CM-RJ45-MG 10GBASE-T module (port 6, later port 7) to reach a Zyxel XS1930. Whenever the copper cable was disconnected for more than about 40 s or the Zyxel rebooted, the link never came back until the module was pulled for a minute or the gateway rebooted; forcing 10G or 1G…
An out-of-the-box ES-48-Lite (1.9.3) was connected to an EdgeRouter Infinity ER-8-XG (2.0.9-hotfix.2) with a UF-RJ45-10G module on each side and a Cat6 cable. A laptop on the switch obtained a DHCP lease from the router only after about a minute and then could not reach the router or the internet…
Between VxRail Dell S5212F-ON TOR switches and Cisco C9500-48Y4C switches, FS.com SFP28 DACs behaved inconsistently: a 5 m cable custom-coded Cisco on one end and Dell on the other came Line Up, Protocol down; a 2 m Cisco/Cisco-coded cable linked; a 3 m cable would not link even with the 2 m…
A QSFP28 100 Gb DAC supplied by Supermicro linked two Dell S5248F-ON (OS10 10.4.3.6) switches fine, but between the Dell and a Supermicro XEM-100 the port showed up, line protocol is down. Multiple FEC and negotiation combinations were tried. The thread received no answers. Hardware involved: Dell…
A short no-name DAC between a UDM SE and a Minisforum MS-01 had worked for months; a new 30 m Ubiquiti UACC-AOC-SFP10-30M active optical cable was recognised by the UDM SE (vendor, part, serial, temperrature, power visible) but no link came up and the SFP port log showed an SFP EEPROM error; on…
The poster wanted to connect a UDM SE (10G SFP+) to an Enterprise XG 24 switch (25G SFP28) and asked whether an SFP+ DAC would work with the SFP28 port falling back to 10G, or whether an SFP28 DAC was preferable. The concern was whether the SFP28 cage would fall back to 10G with an ordinary SFP+…
A UDM Pro (port 11 set to 1G) and a US-16-150W (port 17) connected by a 1 m Ubiquiti DAC (UDC-1) did not talk: the switch showed a link light, the UDM Pro showed nothing. Setting both sides to 1G and rebooting both devices did not help; reversing the cable and removing the parallel copper uplink…
An ADDON JD097C-AO SFP+ DAC worked between two US-48-500W (firmware 3.3.11.3850) but not from a US-48-500W to a US-16-XG (3.7.39.6089): no link lights on either side and forcing 10G made no difference, although mca-dump on the XG showed the module fully parsed (sfpfound true, vendor ADDON, part…
An EdgeRouter 4 (EdgeOS 1.10.0) with the GPON SFP taken from a Bell Home Hub 3000 (Huawei MA5671A, SC connector, DDM readable: 50.9 C, 3.25 V, 8.87 mA, TX 1.36 mW, RX 0.02 mW) logged kernel: Failed to read SFP EEPROM1 at byte 0 val -11!! twelve times a minute although the internet worked. Removing…
On two sites a UNAS Pro (UniFi RJ45 SFP+ module) and a UNVR (UniFi fibre SFP+ module) dropped to 1G after every firmware update or power cycle; rebooting the device, the port or the switch did not help, only physically pulling and reinserting the module (or reseating the fibre) restored an…
After moving a Bell fibre connection from an ER-X to an ER-4 with the ISP's Alcatel-Lucent/Nokia GPON SFP (3FE46541AA / G-010S-P) plugged directly into eth3, the WAN dropped every 3 to 60 minutes; syslog had hundreds of kernel: Failed to read SFP EEPROM1 at byte 0 val -6!! entries and SFP module…
A MikroTik RB4011 connected with an S+DA0001 DAC to a CRS106-1C-5S and a CRS112-8G-IN (all default configuration apart from IP addresses) had no connectivity over the SFP link. The RB4011 SFP+ cage is documented to accept onyl active direct-attach cables, so a passive twinax between it and the two…
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…
After UniFi Network 10.0.140 / switch firmware 7.2.123 several operators saw SFP+ ports (UI optics, UACC-OM-MM-10G-D, MikroTik XS+DA0001 DACs, UACC-CM-RJ45-MG copper modules) flapping on US-XG-16, USW Pro Max, UDM Pro and USW-24-Pro units, with STP State Flapping alerts, ports blocked, and switches…
