[Solved] Slow download speed on AC3100 behind AT&T U-Verse 5268AC modem

[rtn66uftw]

Here is the problem: I have 300 Mbps AT&T fiber connection
- If I used AT&T U-Verse 5268AC FXN modem's wireless, I got around 200 Mbps both download and upload (used dslreports.com/speedtest).
- If I put the U-Verse into bridge mode (link) and connected from one of its LAN ports to the WAN port on the AC3100, I only could get around 15-20Mbps download speed. Upload speed was still roughly the same as before.

AC3100 is running Merlin's v.384.11_2, no QoS or AI Protection, no traffic monitoring per IPs, channel bandwidth 20/40/80MHz

How can I troubleshoot this? Thanks!

 

[ApexRon]

My past experience with 5268AC is not to use bridge mode. Just cascade your AC3100 (plug WAN Ethernet of ASUS into LAN of 5268AC). Yes, you will be double NATing and IPv6 will probably not work but speed should not be impacted. I found that AT&T’s 5268AC had design limitations as did the vDSL connection. I understand that a fiber connection works better.

 

[pinkfloyd1173]

Here is the problem: I have 300 Mbps AT&T fiber connection
- If I used AT&T U-Verse 5268AC FXN modem's wireless, I got around 200 Mbps both download and upload (used dslreports.com/speedtest).
- If I put the U-Verse into bridge mode (link) and connected from one of its LAN ports to the WAN port on the AC3100, I only could get around 15-20Mbps download speed. Upload speed was still roughly the same as before.

AC3100 is running Merlin's v.384.11_2, no QoS or AI Protection, no traffic monitoring per IPs, channel bandwidth 20/40/80MHz

How can I troubleshoot this? Thanks!

It a issue all Att and Uverse owners have. I have Att fiber only, I have the same gateway you do and I was having the same issues you are having. Att rolled out a FW update last november that broke the dmz + mode on those GW, it a known issue.

I use the dumb switch method which by passes the att GW compelety. Now from what I understand the dumb switch method only works if you just have att fiber, no Uverse. I think there is a way to make it work, but it takes some knowledge on how to do it.

Here is the link for the thread about this issue. If yuou want to try the dumb switch method, look on page 2 and you will see the steps on how to do this.

https://www.dslreports.com/forum/r32172124-AT-T-Fiber-5268AC-DMZ-to-Router-Speeds-50-200

Hope this helps.

 

[Maverick3837]

My past experience with 5268AC is not to use bridge mode. Just cascade your AC3100 (plug WAN Ethernet of ASUS into LAN of 5268AC). Yes, you will be double NATing and IPv6 will probably not work but speed should not be impacted. I found that AT&T’s 5268AC had design limitations as did the vDSL connection. I understand that a fiber connection works better.

I have the exact same problem, but with a Calix 844g as my VoIP/Router, and my RT-AC87. My internet provider speeds are not near yours, but nonetheless, with the setup that ApexRon said to do, it works great in my case. I wanted to still use my RT-AC87 for the QOS features and stuff, so I just cascaded both routers and it works. Speeds are exactly the same as running it off my RT-AC87 exclusively. Bridge mode on the Calix 844g will not activate, so there was no other choice.

 

[ApexRon]

I don’t prefer not to use “band-aid” or “workarounds” but was forced to with the 5268AC. A year ago I switched to Spectrum cable and I now have a direct connection from cable modem to ASUS router, an unencumbered connection to internet.

 

[rtn66uftw]

It a issue all Att and Uverse owners have. I have Att fiber only, I have the same gateway you do and I was having the same issues you are having. Att rolled out a FW update last november that broke the dmz + mode on those GW, it a known issue.

I use the dumb switch method which by passes the att GW completely. Now from what I understand the dumb switch method only works if you just have att fiber, no Uverse. I think there is a way to make it work, but it takes some knowledge on how to do it.

Here is the link for the thread about this issue. If yuou want to try the dumb switch method, look on page 2 and you will see the steps on how to do this.

https://www.dslreports.com/forum/r32172124-AT-T-Fiber-5268AC-DMZ-to-Router-Speeds-50-200

Hope this helps.

Thank you!

My past experience with 5268AC is not to use bridge mode. Just cascade your AC3100 (plug WAN Ethernet of ASUS into LAN of 5268AC). Yes, you will be double NATing and IPv6 will probably not work but speed should not be impacted. I found that AT&T’s 5268AC had design limitations as did the vDSL connection. I understand that a fiber connection works better.

Thank you. My previous setup was what you suggested. I want to eliminate the double NAT

 

[jsbeddow]

I can confirm that @pinkfloyd1173 is spot-on correct in his advice: I am also on AT&T fiber and use the dumb switch bypass method as well. It has worked nearly perfectly (without interruption for two plus months), other than one time that I have had to briefly reauthenticate with the 5268AC when I had a power outage (and yes, despite all devices being suppied by UPS power, go figure).

 

[ApexRon]

Thank you. My previous setup was what you suggested. I want to eliminate the double NAT

You now have two workarounds but there’s a third and it’s more of a solution: choose another ISP. I left AT&T, in part, because of the 5268AC and no IPv6 but mostly because of cost (8x the speed of vDSL) for $5 less per month.

 

[pinkfloyd1173]

Thank you!



Thank you. My previous setup was what you suggested. I want to eliminate the double NAT

So I was checking the forums on DSL reports and the Att 5268AC GW just got a new FW update that has fixed the DMZ ip pass thourgh, you now get your full speeds??

Will try it out, but to be honest I like using the Dumb switch method.

https://www.dslreports.com/forum/r32412967-New-software-version-for-Pace-5268AC

 

[rtn66uftw]

You now have two workarounds but there’s a third and it’s more of a solution: choose another ISP. I left AT&T, in part, because of the 5268AC and no IPv6 but mostly because of cost (8x the speed of vDSL) for $5 less per month.

Unfortunately AT&T is the only option in my area :-(

So I was checking the forums on DSL reports and the Att 5268AC GW just got a new FW update that has fixed the DMZ ip pass through, you now get your full speeds??

Will try it out, but to be honest I like using the Dumb switch method.

https://www.dslreports.com/forum/r32412967-New-software-version-for-Pace-5268AC

I turned everything off on Friday and re-did the DMZ IP pass through then restart the whole system once again. Surprisingly now I have full 300 Mbps up and download speed.

Thanks everyone again!