Posted: Mon Oct 06, 2025 17:12 Post subject: Switch config - can't uncheck Auto-negotiate
I have a Linksys WRTG54v2whatever router, and oldie. I am using DDWRT v3.
When I go to switch config page, I'm showing that all 4 ethernet ports that are LAN routed have all checkmarks on "Auto-negotiate, Gigabit, Full Speed, Full Duplex, Enabled". I try to uncheck "Auto-negotiate" on one of the ports, Save/Apply Settings - but it refreshes the page with the checkmark back on. I tried different ways to do it, it just won't unset those settings. How do I unset those settings???
The reason I'm even trying to do this is because the clients are connecting on Half Duplex to the router, so I'm trying to troubleshoot this, and it seems the router is the culprit because my client has "auto-negotiation" off, which means half duplex is set by the router even though it says full duplex on the router's Switch config page?
Something's going on. If anyone could pls help, would be greately appreicateded.
Thanks. I didn't think the build number would be relevant for this.
So the router is capable of Full-Duplex, but just can't change settings for it? Or the page is the standard template, and the router is actually not Full Duplex?
and it seems the router is the culprit because my client has "auto-negotiation" off
Auto-negotiation must be enabled on both sides (router and client).
Then it will work...
If it is only enabled on one side, it will not work and one of the devices may make strange decisions...
The possible speed is then determined by parallel detection, but the duplex mode cannot be detected and half-duplex is usually selected.
The remote station without auto-negotiation must then be set to half-duplex, otherwise a duplex mismatch error will occur. _________________ Quickstart guides:
Ok, thanks. I will keep researching. It might be the Linux driver for the USB ethernet dongle that's not supporting Auto-negotiation. And it sounds like you can have Full Duplex with one device having auto-negotiate OFF if and only if you can manually set both devices to Auto-negotiate OFF and Duplex FULL. That's what Google Gemini is saying at least. And it seems I cannot change things on the router or the USB ethernet dongle with the Linux kernel driver for it.
Just saw someone say that it's my USB ethernet dongle's driver not being properly detected on Linux. So I think it's not the router, it's the my USB ethernet adapter. Thank you for your help!
