LAN1 always connects at 100 mbps

[rahuljawale]

I have a year old RT-N66U with Firmware:3.0.0.4.372.30_3 (Merlin build). The LAN1 port of my RT-N66U always connects at 100 mbps no matter what.

I tried,
1. with different Ethernet Adapters like, Intels, Marvells, Realteks
2. changing the cable and even made one myself.
3. Upgrading/Downgrading firmware
4. Stock ASUS firmware,
5. Multiple full resets (with nvram erase)

Could this be a hardware problem?

Here is a screenshot taken from Tools -> Sys Info section.

 

[RMerlin]

Try one of the other ports just to see if it makes a difference.

Also make sure the cable is rated Cat5e or Cat6 - older Cat5 cables cannot support gigabit speeds. Also note that I have seen some cheaper RJ-45 connectors not properly work at gigabit speeds either when crimping your own cable (that happened to me a few years ago).

I assume you are using a proper wiring order when crimping your own cable (EIA / TIA 568, A or B)?

 

[rahuljawale]

Thanks for your reply Merlin. Yes, I am using standard B layout for wiring. And the same cable can connect at 1000 mbps on LAN2/3/4 with the same adapter.

 

[sm00thpapa]

May I ask what's on the other end of the cable?

 

[RMerlin]

Thanks for your reply Merlin. Yes, I am using standard B layout for wiring. And the same cable can connect at 1000 mbps on LAN2/3/4 with the same adapter.

If just moving the same cable to another port gives you 1000 Mbps, then I would RMA the router - sounds like an issue with the first port.

 

[rahuljawale]

Thanks Merlin.

@Smoothpapa, it's the NAS that I built on Supermicro X7SPA-HF-D525 (I hope I got that right ). This board carries two high quality Intel NICs.

 

[GoNz0]

last time i saw this 2 pins in the lan socket had crossed, i pulled then apart with a pin and it worked fine.

 

[rahuljawale]

Thanks Gonzo. I checked that too. Cleaned the connectors with an eraser. But that did not help either.