Airport Extreme Speed Question

I assume that you have already performed the standard troubleshooting steps.....like powering down and restarting the AirPort Extreme as well as the Mac.

As it stands now, we don't really know whether you have a potential AirPort Extreme issue or a Mac issue.

Do you have another computer that you could connect to the AirPort Extreme using an Ethernet cable......for a temporary test......to see if the test computer is also slow using an Ethernet connection?

If you try another computer and it operates at full speed, then that tells you that the AirPort Extreme is operating correctly, and something is amiss with the Mac.

If you try another computer and it checks out at the same slow speed, then the troubleshooting focus shifts to the AirPort Extreme.

The only field I am not sure about is in the Proxy parameter *.local, 169.254/16. But I do not think that would influence link speed.

You're right. They do not affect link speed and those would be the default settings ... unless you are running a proxy server on your local network.

The issue is not so much if you had changed anything, but to verify that you have the best possible settings on the Hardware tab for your situation. There may be a potential communication issue between the modem and the Extreme that, strangely enough, only manifests itself on the wired side ... but without getting a traffic capture it would be hard to tell.

The other option at this point is to perform a complete power recycle of your networking hardware to see if this can resolve it. Check out the following AirPort User tip for the details on how to do this. Note: You can skip the part of performing a "factory default" reset on the Extreme at this point.

No sure why at the moment, but there is something you can try to see if your iMac is getting the best possible bandwidth with an Ethernet connection by going to System Preferences > Network > Ethernet > Advanced > Hardware

By default, the settings should be something like:

• Configure: Automatically
• Speed: 1000baseT
• Duplex: full-duplex, flow-control
• MTU: Standard (1500)
• AVB/EAV Mode is disabled.

I suggest that you compare your iMac's settings. You can then try different ones to see if there is any improvement. To do so, change the Configure setting from Automatically to Manually. Start with the Duplex settings, then MTU. For MTU, depending on if you have PPPoE or not, you can try a Custom setting of 1492. If you don't get PPPoE service, I suggest also trying the Jumbo (9000) setting.