RT-AC86U (386.11) in Repeater Mode only allowing 4 Wifi Clients at a time?

[Futuristic]

Hello Guys, been awhile since I've been stumped by router issues, but I'm over here at my mothers house visiting and trying to solve a rather frustrating issue.

They have an Arris cable modem / wifi router that was provided by their ISP - https://www.compasxstream.com/compas/page/internet - I don't know the model, but it doesn't seem like the modem is the issue here from what I can tell, but I may be wrong.

They also have a RT-AC86U that I had them purchase awhile ago that is running the latest Merlin Firmware. (386.11) I've got it running in Repeater Mode connecting via 5G from the Arris and it sits by their TV where 3 devices are connected via Ethernet. It's an old house that is very long from one end to the other and the modem is all the way on the other side, hence the reason for repeater mode. Ethernet seems to work great, so no issues there... But the WIFI on the RT-AC86U seems to only allow 4 devices at a time. When I try connecting the 5th or more they will not get an IP address no matter what. Meanwhile, the ones that are connected work great and the Wireless connection is solid/strong. All the Ethernet ports are unaffected by this behavior. The main router doesn't seem to limit any wifi connections when you use it's Radios, so i have no idea whats going on here

Is this some sort of limitation with Repeater mode or? I've never run into this issue before, but I also don't normally use repeater mode for my own home and setup. I considered it may be an issue with the Arris, but I did find a thread from about 2019 on here where a few people were having the same issue and it didn't appear to be solved and the thread was dead.

Hoping you guys can help me solve this rather frustrating problem. I"m considering having them swap out this 4 year old Arris modem with their ISP, but I wanted to see what kind of thoughts you savvy networking guys might have

Thanks for any insight or help you can provide!

 

[drinkingbird]

Hello Guys, been awhile since I've been stumped by router issues, but I'm over here at my mothers house visiting and trying to solve a rather frustrating issue.

They have an Arris cable modem / wifi router that was provided by their ISP (https://www.compasxstream.com/compas/page/internet0 - I don't know the model, but it doesn't seem like the modem is the issue here from what I can tell, but I may be wrong.

They also have a RT-AC86U that I had them purchase awhile ago that is running the latest Merlin Firmware. (386.11) I've got it running in Repeater Mode connecting via 5G from the Arris and it sits by their TV where 3 devices are connected via Ethernet. It's an old house that is very long from one end to the other and the modem is all the way on the other side, hence the reason for repeater mode. Ethernet seems to work great, so no issues there... But the WIFI on the RT-AC86U seems to only allow 4 devices at a time. When I try connecting the 5th or more they will not get an IP address no matter what. Meanwhile, the ones that are connected work great and the Wireless connection is solid/strong. All the Ethernet ports are unaffected by this behavior. The main router doesn't seem to limit any wifi connections when you use it's Radios, so i have no idea whats going on here

Is this some sort of limitation with Repeater mode or? I've never run into this issue before, but I also don't normally use repeater mode for my own home and setup. I considered it may be an issue with the Arris, but I did find a thread from about 2019 on here where a few people were having the same issue and it didn't appear to be solved and the thread was dead.

Hoping you guys can help me solve this rather frustrating problem. I"m considering having them swap out this 4 year old Arris modem with their ISP, but I wanted to see what kind of thoughts you savvy networking guys might have

Thanks for any insight or help you can provide!

Haven't heard of that specific issue, definitely should not be an issue of repeater mode. So the wireless connects and just can't get an IP? Have you looked at logs in the Arris - make sure it has a large enough DHCP scope etc?

Anything in the Asus logs?

Is it just one specific device that can't be the 4th or have you tried several (i.e. a device that connects successfully as #4 can't connect as #5)? And the first 4 wireless devices are still working fine after the 5th connects?

In the Asus, does it have the MU-MIMO option when in repeater mode? Try disabling that, and also universal beamforming if it is enabled (explicit/AC beamforning should be ok but you can try disabling both at first just to see). Both features, MU and both beamforming methods do need to track clients and do "special things" for each client so maybe hitting some sort of limit on that. Universal beamforming often causes more issues than it helps so I'd leave that disabled regardless.

Did you have the same issue on previous firmwares? 386.11 just came out so you may have run into a bug.

 

[bbunge]

Why are you using Merlin firmware for a repeater? You gain no features as I'm pretty sure he tests only the router functions. As it is recommended to use Asus firmware for mesh systems you may benefit from Asus factory firmware for your repeater.

 

[Futuristic]

Haven't heard of that specific issue, definitely should not be an issue of repeater mode. So the wireless connects and just can't get an IP? Have you looked at logs in the Arris - make sure it has a large enough DHCP scope etc?

Anything in the Asus logs?

Is it just one specific device that can't be the 4th or have you tried several (i.e. a device that connects successfully as #4 can't connect as #5)? And the first 4 wireless devices are still working fine after the 5th connects?

In the Asus, does it have the MU-MIMO option when in repeater mode? Try disabling that, and also universal beamforming if it is enabled (explicit/AC beamforning should be ok but you can try disabling both at first just to see). Both features, MU and both beamforming methods do need to track clients and do "special things" for each client so maybe hitting some sort of limit on that. Universal beamforming often causes more issues than it helps so I'd leave that disabled regardless.

Did you have the same issue on previous firmwares? 386.11 just came out so you may have run into a bug.

Hey, thanks for the reply.

It doesn't appear to be any specific device that can't connect. If I disconnect one of the 4 using WiFI, another one will be able to connect and take its slot and it works fine. I put Merlin's Firmware on it when they first got the router a year or so ago and the 386.11 update just happened to be posted the day I got here and I was dealing with this, so I just updated it. Hoping maybe it would solve the issue inadvertently. I don't think it's a bug with the firmware per say, I was just trying to provide details about what I had loaded on the AC86U.

In repeater mode, a good portion of the normal options are just disabled and removed, so I don't see anything regarding MU-MIMO or beamforming. It gets pretty stripped down in repeater mode and there's not a lot of settings regarding the WiFi

It's very bizarre and I'm starting to think it might be some sort of clash with this Arris in some strange way. I run a N66U as an AP in my own home and I've never run into this issue.

As far as logs, I don't see anything in particular on the main router, looks like just internet packet logs to outside IP's.. The ASUS might provide more info, but at the moment I'm not seeing anything that provides any particular useful info in regards to this situation - "Disassociated because sending station is leaving" is basically what all I'm seeing.. I will see if I can get it to provide more somehow.

Thanks again for the reply.

 

[ColinTaylor]

As @drinkingbird suggested, check the size of the DHCP pool on the main router just to make sure it's not set to something stupidly small.

I presume you've tried rebooting the main router?

 

[Futuristic]

Thanks for the reply, Colin.

Here's some screen shots of the main routers settings. Doesn't look like the pool is limited in any way. 2-254 seems pretty normal. I did change the default LAN IP, because I noticed the AC86U was giving itself a 192.168.50.X when set to DHCP even though the router was originally at 192.168.0.1. No clue why that was happening. So I manually set the AC86U to 192.168.50.50 to hopefully clear that up and it seemed to help. I may try giving DHCP a try on it again and see what happens. I've reset the modem and the 86U several times and started from scratch probably 10 times. Still happening no matter what configuration I use.

LAN Settings:

5G Wireless Settings:

 

[Futuristic]

Just tried my last resort and its a no go. When I set the AC86U to DHCP it somehow gets the main routers IP of 192.168.50.1 and then obviously I cannot connect to it. I tried manually setting it to 192.168.50.2 and adding it to the reserved client list in the main router and when I refresh that list the IP keeps changing to something else like 192.168.50.19 etc.. even though its hard set on the AC86U and added to the reserve client list... I can refresh that page 10 seconds later and it will be a different IP once again. I'm perplexed by it all. I've never seen anything like this and I'm pretty much convinced its the Arris at this point. Nothing really makes any sense. I've setup many home networks for friends and family and its usually like a 15-30 minute job at the most. I've spent over 2 days trying different configurations and basically have gotten nowhere, lol.

 

[jeff3820]

I'd putting in stock Asus firmware and then do a full factory reset...then see if the behavior changes.

 

[drinkingbird]

Just tried my last resort and its a no go. When I set the AC86U to DHCP it somehow gets the main routers IP of 192.168.50.1 and then obviously I cannot connect to it. I tried manually setting it to 192.168.50.2 and adding it to the reserved client list in the main router and when I refresh that list the IP keeps changing to something else like 192.168.50.19 etc.. even though its hard set on the AC86U and added to the reserve client list... I can refresh that page 10 seconds later and it will be a different IP once again. I'm perplexed by it all. I've never seen anything like this and I'm pretty much convinced its the Arris at this point. Nothing really makes any sense. I've setup many home networks for friends and family and its usually like a 15-30 minute job at the most. I've spent over 2 days trying different configurations and basically have gotten nowhere, lol.

50.1 on the LAN is default for that router, it probably isn't getting it from DHCP, it sounds like a bug with AP mode. I'd move to stock firmware, if all you're looking for is repeater mode. Sounds like maybe that mode is not working correctly with Merlin. I don't think it is getting the main router's IP, I think it is putting its default IP on there, just coincidence that you changed the main router to 50.1 based on having seen that behavior before.

In fact to avoid any possible conflicts I'd probably change the ISP router back to its default. Heck while you're at it, reset their entire router to defaults, and do the same on the asus after you load the latest stock firmware (WPS reset method). Configure the ISP router first (if there are any settings you want to change, like restricting it to AC or N/AC. I'd probably disable frame burst mode, but it probably isn't hurting anything.

 

[ColinTaylor]

IIRC the Asus will default to it's normal address (50.1) until it's able to connect to the parent router to get the correct IP details. So you might just as well manually configure its IP address to avoid any confusion.

 

[Futuristic]

Well thank you for all your suggestions, guys.

I reset the main router back to its defaults and its default IP and I loaded the stock Firmware which is actually missing the "Tools" tab that Merlins Firmware has. So less options on that. Regardless, it's still doing the same thing. Maybe even worse behavior. Now I can't get anything to connect to the repeaters radios, while the Ethernet works occasionally. I even tried setting a manual IP on my ipad to 192.168.0.100 and it says theres no internet. I'm also having to restart the AC86U over and over as sometimes the Ethernet ports aren't getting internet even though the radio is connected to 5G and everything appears to be connected. Then magically one of the restarts will go through and everything is back up and running. I had to set it to a manual IP again because for some reason, the main router is not populating the DNS section with its address when the AC86U is set to DHCP. I'm at a loss and I'm pretty burnt on the whole process at this point. Seems like the best config i had was with Merlins firmware and the router set to 192.168.50.1 and the repeater at 50.50 -

It has to be something to do with the Main Arris router. The AC86U appears to be working like I would expect it to, so I don't know what else to do besides swapping out the modem/router for a newer one or a different model. I use the AC86U as my main router in my own home and it works flawlessly with over 30+ devices connected to it. This one seems like it's behaving just like mine does when configuring and whatnot. So I don't think there's actually a problem with it.

If you guys got any more suggestions, I'm all ears. At this point I've exhausted all possible options I could think of.

Thanks again for all your replies, I appreciate it.

 

[drinkingbird]

Well thank you for all your suggestions, guys.

I reset the main router back to its defaults and its default IP and I loaded the stock Firmware which is actually missing the "Tools" tab that Merlins Firmware has. So less options on that. Regardless, it's still doing the same thing. Maybe even worse behavior. Now I can't get anything to connect to the repeaters radios, while the Ethernet works occasionally. I even tried setting a manual IP on my ipad to 192.168.0.100 and it says theres no internet. I'm also having to restart the AC86U over and over as sometimes the Ethernet ports aren't getting internet even though the radio is connected to 5G and everything appears to be connected. Then magically one of the restarts will go through and everything is back up and running. I had to set it to a manual IP again because for some reason, the main router is not populating the DNS section with its address when the AC86U is set to DHCP. I'm at a loss and I'm pretty burnt on the whole process at this point. Seems like the best config i had was with Merlins firmware and the router set to 192.168.50.1 and the repeater at 50.50 -

It has to be something to do with the Main Arris router. The AC86U appears to be working like I would expect it to, so I don't know what else to do besides swapping out the modem/router for a newer one or a different model. I use the AC86U as my main router in my own home and it works flawlessly with over 30+ devices connected to it. This one seems like it's behaving just like mine does when configuring and whatnot. So I don't think there's actually a problem with it.

If you guys got any more suggestions, I'm all ears. At this point I've exhausted all possible options I could think of.

Thanks again for all your replies, I appreciate it.

As you say it could be something with the main router's wifi, have you connected anything to that on wifi to see how it works?

But the 4 device limit (when running merlin) isn't something that would really point to the main router's wifi having issues. Possibly it's mac address table or routing performance. At this point I'm starting to wonder if your 86U is dying (a common issue with that model).

 

[Futuristic]

Yes, the main routers wifi seems to work fine. No speed issues or anything that appears out of the norm. All the devices connect to it properly and there's no limit on clients from what I can tell. The radios are bit weak but that's about it.

Now all of the sudden the wifi on the AC86U is working again at random.. I just gave up for the day and left it in it's current state where nothing would get an IP from it and my ipad suddenly connected to it just now, but its really laggy and slow. Reconnect to the main routers WiFi and the speed is back. Tried again moments later with my phone and its back to not letting anything connect, even the iPad. This is beyond frustrating...

You really think it's the 86U? It's only a year old or less even... My own 86U has been going strong for like 4-5 years now I'm guessing?? I bought it when they first came out and haven't had any issues with it.

I do notice in the main router client list the AC86U is the only one getting some sort of IPV6 address and its also the 192.168.0.5 address in that list. There's no settings to turn off IPV6 in repeater mode and the IPV6 section on the main router isn't populated with any other IPV6 stuff beside the local link address. Could this be something to do with it?

 

[drinkingbird]

Yes, the main routers wifi seems to work fine. No speed issues or anything that appears out of the norm. All the devices connect to it properly and there's no limit on clients from what I can tell. The radios are bit weak but that's about it.

Now all of the sudden the wifi on the AC86U is working again at random.. I just gave up for the day and left it in it's current state where nothing would get an IP from it and my ipad suddenly connected to it just now, but its really laggy and slow. Reconnect to the main routers WiFi and the speed is back. Tried again moments later with my phone and its back to not letting anything connect, even the iPad. This is beyond frustrating...

You really think it's the 86U? It's only a year old or less even... My own 86U has been going strong for like 4-5 years now I'm guessing?? I bought it when they first came out and haven't had any issues with it.

I do notice in the main router client list the AC86U is the only one getting some sort of IPV6 address and its also the 192.168.0.5 address in that list. There's no settings to turn off IPV6 in repeater mode and the IPV6 section on the main router isn't populated with any other IPV6 stuff beside the local link address. Could this be something to do with it?

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Unlikely to be v6 related - but disable v6 on the ISP router anyway, you don't need it. FE80 are link local IPs so the asus probably assigns itself one, no big deal. But I'd disable it on the ISP router to eliminate that as a possibility.

Now you say the wifi on the ISP router is weak (as is typical of many Arris routers), maybe once you exceed 4 devices it is just too much for that backhaul to handle? That isn't the normal behavior I'd expect especially if the other 4 devices are dormant and not using bandwidth. Just a thought that maybe placement halfway between ISP router and living room would be better.

Did you factory reset the Asus before or after returning to stock firmware? It should be done after (using the WPS button method).

Did you test the 86u in AP or router mode temporarily (ideally AP mode hardwired near the ISP router) to see if it has the same problem? If so, try router mode. If it still has the issue in router mode, I think it is a hardware issue at that point.

Even if you only bought it a year ago, the AC86 is quite old. Many revisions had issues with radios burning out. So while I'm not saying that is definitely the case, it is a possibility.

Only other random thought is one of the 5 devices may be misbehaving and somehow locking up the wifi - but I'd expect all the other devices to have issues at that point. But if one of the devices is a hub like Alexa etc they do tend to send a lot of MDNS and other "crap" out and it could be saturating the weak connection potentially.

 

[Futuristic]

There seems to be no way to disable the IPV6 section. I guess I could just erase the local link address and save, but that page I pictured above is basically what you get for IPV6. I did reset it with the WPS method after I loaded the stock firmware.

On another note... They originally had an N66U that was working great and then one day they told me it wasn't powering up. That's when I had them get this AC86U. Well, I was downstairs today and I found the N66U on a shelf and plugged it in and it fired right up no problem. Must have got unplugged by accident or something. I reset it with the WPS method and configured it just like the AC86U. DHCP and connecting through the 5G in repeater mode. And what do you know... It works flawlessly. It even populates the DNS settings to the actual DNS IP's the main router is getting. It is super quick and runs how I would expect it to. I've got 5 WiFi devices connected to it right now no problem. It also has a whole section for WiFi settings that seems to be stripped out of the AC86U in repeater mode. It has johns fork firmware on it (47EB) I also still have the AC86U connected and configured and its working fine at the moment. So it looks like the main router might not be the problem here after all.

And on an even another note.. When I woke up this morning everything was working great on the AC86U. Devices are connecting to the WiFi all of the sudden and it seems like everything is fine. I noticed this the other day that after it sits overnight it starts working normally. I haven't tried 5 WiFi devices today just yet, but I'm wondering if this has something to do with the DNS settings. Maybe I need to manually input the ISP's DNS in there instead the routers address like I had been doing. It's all kind of mystical at this point, lol.

What are your thoughts on that? I may just put this N66U back there and call it a day because it seems to work as expected. I had it up and running in 5 minutes. I don't know, I'm torn because the AC86U has really good range, even better then the N66U when it's working right. I'm gonna try and connect the 5 devices to it now and see what happens.

 

[Futuristic]

Well, I just connected 5 devices to the AC86U and they all connected this time and everything is super fast. Ethernet and WiFi both really zippy. I have no idea what is going here and why sitting overnight seems to fix whatever problem is going on. I almost don't want to manually set the DNS on the 86U for fear of going through this all over again. This is the first time I've actually had 5 devices connected.

So, at the moment I have the AC86U manually IP configured and connected to the 5G band in repeater mode and I also have the N66U connected to the 5G band in repeater mode and everything is working normally. The best its worked since I've gotten here. So strange.

What do you think is going on here?

 

[Futuristic]

Thank you for all your suggestions and help, drinkingbird! I think you're right about it being some sort of hardware problem with AC86U. It just crapped out now and I wasn't getting internet on the ethernet cables out of nowhere but the wifi was still working??

I just unplugged it and fire up the N66U in it's place and I'm going to call it a day (or 3) and retire the AC86U. There's definitely something wrong with it now that I've seen the N66U in action. Everything is working great with that, so I'm just gonna roll with it for now.

Thanks to all the others who contributed and provided some help. I learned a few things I didn't know, so that was helpful too.

PROBLEM SOLVED!

 

[drinkingbird]

There seems to be no way to disable the IPV6 section. I guess I could just erase the local link address and save, but that page I pictured above is basically what you get for IPV6. I did reset it with the WPS method after I loaded the stock firmware.

On another note... They originally had an N66U that was working great and then one day they told me it wasn't powering up. That's when I had them get this AC86U. Well, I was downstairs today and I found the N66U on a shelf and plugged it in and it fired right up no problem. Must have got unplugged by accident or something. I reset it with the WPS method and configured it just like the AC86U. DHCP and connecting through the 5G in repeater mode. And what do you know... It works flawlessly. It even populates the DNS settings to the actual DNS IP's the main router is getting. It is super quick and runs how I would expect it to. I've got 5 WiFi devices connected to it right now no problem. It also has a whole section for WiFi settings that seems to be stripped out of the AC86U in repeater mode. It has johns fork firmware on it (47EB) I also still have the AC86U connected and configured and its working fine at the moment. So it looks like the main router might not be the problem here after all.

And on an even another note.. When I woke up this morning everything was working great on the AC86U. Devices are connecting to the WiFi all of the sudden and it seems like everything is fine. I noticed this the other day that after it sits overnight it starts working normally. I haven't tried 5 WiFi devices today just yet, but I'm wondering if this has something to do with the DNS settings. Maybe I need to manually input the ISP's DNS in there instead the routers address like I had been doing. It's all kind of mystical at this point, lol.

What are your thoughts on that? I may just put this N66U back there and call it a day because it seems to work as expected. I had it up and running in 5 minutes. I don't know, I'm torn because the AC86U has really good range, even better then the N66U when it's working right. I'm gonna try and connect the 5 devices to it now and see what happens.

AP mode doesn't need DNS other than checking for firmware updates.

 

[drinkingbird]

Thank you for all your suggestions and help, drinkingbird! I think you're right about it being some sort of hardware problem with AC86U. It just crapped out now and I wasn't getting internet on the ethernet cables out of nowhere but the wifi was still working??

I just unplugged it and fire up the N66U in it's place and I'm going to call it a day (or 3) and retire the AC86U. There's definitely something wrong with it now that I've seen the N66U in action. Everything is working great with that, so I'm just gonna roll with it for now.

Thanks to all the others who contributed and provided some help. I learned a few things I didn't know, so that was helpful too.

PROBLEM SOLVED!

It is possible it was just a distance issue, did you try the 86 somewhere closer to the ISP router? Understood that hardwired devices are needed, just curious as a test. Seems unlikely though based on the symptoms you're describing, but these things don't always make sense. The N router with smaller channel width is going to have better range than AC typically, but probably not much difference (and AC has some newer features to increase range which should mostly cancel it out).

Unfortunately that AC86U router is known for hardware problems, so I think yours may be dying or you got a bum one to start with. If the N is getting you the performance and speed you want, sounds like you're set. But you could test the 86 more if you want to see if it can be used for something else, probably drop it back to 386.7_2, factory reset with WPS, and see if it works as a standard router or AP reliably. If not, probably time for the bin.

I believe this is one of the models prone to heat issues so possibly wherever it was it wasn't getting good enough ventilation etc. Once the thermal pads/paste degrade it will only work for short periods without issues.

 

[drinkingbird]

Well, I just connected 5 devices to the AC86U and they all connected this time and everything is super fast. Ethernet and WiFi both really zippy. I have no idea what is going here and why sitting overnight seems to fix whatever problem is going on. I almost don't want to manually set the DNS on the 86U for fear of going through this all over again. This is the first time I've actually had 5 devices connected.

So, at the moment I have the AC86U manually IP configured and connected to the 5G band in repeater mode and I also have the N66U connected to the 5G band in repeater mode and everything is working normally. The best its worked since I've gotten here. So strange.

What do you think is going on here?

Oops missed this one. It really does sound like 1 of 2 things:

Heat - when it is dormant at night and potentially cooler in the house, it cools down and starts behaving better, until heavy use and daytime temps go up.
Distance - Less stuff going on at night, less neighbors on wifi, less microwaves running, etc, i.e. less noise to interfere with that wireless backhaul.

My guess is probably #1. Not that it is exceeding its rated temperature necessarily, but that whatever is dying (probably wireless radio or the CPU) is no longer able to handle anywhere near its rated temps.