Solved Stuck at 100 MBPS On GT-AC2900 WAN Port

[TheCursedRouter]

Hey everyone,

Wanted to make a post here since I had a few good leads here but none solved my issue.

The issue:
WAN port stuck at 100 mbps on my Asus GT-AC2900 (with actual speeds only reaching 10mbps max on the 10/100)

Things I tried to fix it:
Disabling QoS, multiple CAT 5E cable replacements, firmware upgrades and downgrades, comcast technician support, 2 different modems, mac address cloning, and I even tried to learn the qualcomm commands to force a 1gig duplex (I think that's what it's called?) since robocfg isn't available on these routers (as some of the other more experienced users here have seemed to try). Merlin is also no help since it apparently isn't supported on this hardware? Asus support refered me to fill out a form to recreate the issue in their lab setting but that would have taken too long and at that point I decided I needed to return the router since it had to be a hardware issue.

The solution:
The WAN port must be defective because I tried one last attempt to solve the issue after I did some research about using a LAN port as a WAN port. I did this by going into the settings, enabling dual WAN, setting LAN1 as the primary port and WAN as the secondary. Then poof, 400mbps speeds. Faster than the speeds I was expecting given my circumstances with the comcast support.

My recommendation:
If you tried all the troubleshooting I did (minus the qualcomm commands since there simply isn't enough documentation there yet) try your other LAN ports as primary WAN's and see if those work. If that doesn't fix your problem I'd say all your ports are probably defective. Don't go down a 4 day rabbit hole of troubleshooting research like I did and just go try to get a refund.

Hope this helps some people!

 

[L&LD]

What you may have not tried is a switch between your ISP and your router to the WAN port (of the router). That usually solves a lot of issues for people with flakey Ethernet cable (some ports simply don't like the brands you have used/tried).

RMerlin does support your router, even if only experimentally at the moment.

About | Asuswrt-Merlin (asuswrt-merlin.net)


Instead of going down a 4-day rabbit hole, you should have posted your issues here first.

 

[Geddric]

Woah, so, what's going on here? Same issue for me in the Charlotte Metro area. See this link for details. I'm going to try what you suggest right now.

Has my AC-68P gone bad? EXTREMELY slow upload speeds only on LAN on gigabit internet

Hello all, I just upgraded my Xfinity service today from the 200mbps plan to the gigabit plan. I am now seeing EXTREMELY slow upload speeds (like 0.5 mbps) but ONLY on LAN for some reason. I have power cycled everything multiple times (modem, router, PC) and the download speeds have picked up...

www.snbforums.com

 

[Geddric]

I did it the LAN/WAN port switch thing, but it didn't make a difference for me. Although, mysteriously it jumped up to between 280 to 340Mbps down now. I'm still not getting the 400 guaranteed or the 500Mbps they registered on their equipment before the Tech left yesterday, so it's still not good.

 

[gcirish2000]

Hey everyone,

Wanted to make a post here since I had a few good leads here but none solved my issue.

The issue:
WAN port stuck at 100 mbps on my Asus GT-AC2900 (with actual speeds only reaching 10mbps max on the 10/100)

Things I tried to fix it:
Disabling QoS, multiple CAT 5E cable replacements, firmware upgrades and downgrades, comcast technician support, 2 different modems, mac address cloning, and I even tried to learn the qualcomm commands to force a 1gig duplex (I think that's what it's called?) since robocfg isn't available on these routers (as some of the other more experienced users here have seemed to try). Merlin is also no help since it apparently isn't supported on this hardware? Asus support refered me to fill out a form to recreate the issue in their lab setting but that would have taken too long and at that point I decided I needed to return the router since it had to be a hardware issue.

The solution:
The WAN port must be defective because I tried one last attempt to solve the issue after I did some research about using a LAN port as a WAN port. I did this by going into the settings, enabling dual WAN, setting LAN1 as the primary port and WAN as the secondary. Then poof, 400mbps speeds. Faster than the speeds I was expecting given my circumstances with the comcast support.

My recommendation:
If you tried all the troubleshooting I did (minus the qualcomm commands since there simply isn't enough documentation there yet) try your other LAN ports as primary WAN's and see if those work. If that doesn't fix your problem I'd say all your ports are probably defective. Don't go down a 4 day rabbit hole of troubleshooting research like I did and just go try to get a refund.

Hope this helps some people!

THANK YOU for posting this! I've had this same issue for the past two days and have tried every single solution you tried prior to finding this. Enabled Dual WAN, set the a LAN port as primary Wan, and problem instantly fixed! Much appreciated.

 

[Darkje]

So I had the same issue... And apperantly my cat6 cable got some issues. After replacement it was fixed. So many to obvious but it's worth the try.

 

[Rocketboy235]

Yep, recently started having a similar issue with my AC86U. About 2-3 years old. Almost forgot about Dual WAN and then remembered later and that saved the day