RT-AC86U intermittently but constantly dropping Internet Connection

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Occasional Visitor
I think there was recommendation that DCHP query frequency to be (aggressive) Normal ?
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New Around Here
I would factory reset. Up there on @L&LD's tagline he has some great troubleshooting directions (https://www.snbforums.com/members/l-ld.24423/#about). Hard to troubleshoot more as you give few details of your setup, scripts you are using, unique settings etc. The 86U had problems with recent updates that require significant user intervention in some cases, you could read the 384.19 thread to get an idea if that is what's going on for you.
Apologies for the time lapse in a reply - the router had been working fine for the past 3 weeks or so, up until a couple of days ago when I had to reboot the router 8 or 9 times within a 20-minute span. One thing I noticed, though, is that this time there was a lot more network traffic than usual because my main PC was busy encoding some video files, with the output going to a network drive. It's as if the router has a low limit on the total network traffic it can handle at once (internet, LAN, file read/write, media streaming from Netflix or Plex, etc all combined). It being a gigabit router, its limit is 1 gigabit per second of data. I don't have any idea if I had actually reached that limit, but I highly doubt it. And besides, even if I had reached it, I wouldn't expect the router to just stop working... I'd expect there to be a bottleneck so that the data flowed slower, but it did still flow.

Anyway, just a few minutes ago I reverted my firmware back to version I think I read somewhere that version xxxxxxxxx384xxxxx was stable, but I don't remember where I read that and to be honest, I'm not 100% sure that I did read it. Anyway, that was the latest version of 384 that I found on Asus' website, so that's what I'm trying now. Fingers crossed.


New Around Here
Why would you even think about rendering video in a network drive? OMB
Why not? The CPU can't re-encode the video at a speed such that the write to the drive can't keep up, even to a network drive, so it didn't seem to be an issue. This was a one-time thing that I set up quickly though - if it was something that I did with any sort of frequency, I'd probably set it up to avoid network drives. In any case, the specific process that was causing the network traffic probably doesn't matter - it's the fact that the traffic was there (regardless of the process) that seems more relevant.


New Around Here
Well, so much for the firmware idea. It just happened again, less than 2 hours after I reverted the firmware. And no more network traffic than usual. I don't see anything in the system logs that might indicate what happened - the only logs that show are the logs that happened after the reboot (I can't get into the router page to grab the logs before I reboot). I don't really know what info might be helpful.

I don't really have any "unusual" settings, and no scripts:
  • I have my 2G and 5G wireless networks set up, both using WPA2 security.
  • I have a variety of devices connected:
    • Wired:
      • Main PC (static IP)
      • Media server PC (static IP) - this is where much of my storage capacity is located
      • Landline ATA device (static IP)
      • Roku media player
    • Wireless:
      • Printer (static IP)
      • Cell phone
      • GF's cell phone
      • Work laptop
      • GF's laptop
  • Four of those devices are assigned a static internal IP (as noted above).
  • I have one port opened up for remote desktop purposes from my work laptop to my main PC.
  • I have a DDNS set up (no-ip.com).
  • While troubleshooting this issue, somewhere in this thread it's suggested to use and as the WAN DNS settings, so I've done that. Previously, it was set to connect to the DNS server automatically.
  • DHCP frequency is set to aggressive (I don't remember if this is the default or not).

As far as I know all other settings are factory default.


New Around Here
Hi all,

Just signed up as I have a very similar issue.

I have an ASUS Rt-AC68U that's about 3 years old. I have started getting a constant network dropout around the same time everyday since setting up a UNIVIEW NVR. The network seems to stay up but I lose internet. I'm on the 384.19 Merlin firmware. I've read through the posts and the only thing I can find is my DCHP mode was set on Aggressive, I've just changed to Normal mode. I'll report back at around 7.30PM AUS time.


New Around Here
Update: Lasted less than 30 min and another network drop out

Have now downgraded firmware to 384.13 as recommended in another post. Bit of a hail mary
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Lotta Cox

Senior Member
Don't always blame the router. Your modem may be dropping connections. Check modem log if you can for critical events like T3 and T4 timeouts.
Check signal levels too if you can.

I think what helped me was cloning the modems mac to the router. It's been cloned a long time and I never get the red light of death anymore. YMMV
Query set to normal mode

I started getting tiny brief internet interruptions recently. No disconnects.

Fri Jan 1 2021
Warning (5)Dynamic Range Window violation
Fri Jan 1 2021
Critical (3)Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=4a:fd:62;CMTS-MAC=:77:e6:75;CM-QOS=1.1;CM-VER=3.1;


Regular Contributor
In my experience 95+% of the time these issues are with the ISP...their servers or their infrastructure...including the drop to your residence. When this happens, the first thing I do is run a line monitor to try to capture the timing/frequency of the outages and the latency of the line before and after the outages. Here is a link to some very useful software: https://emcosoftware.com/ping-monitor. The paid version of the software is very good...there is a free version that is full functional for monitoring. Set it up to monitor 3 sites...I used,, and After 24 hours the report can be setup to show uptime, latency, while logging the times of incidents.

When the internet is disconnected does it ever come back on its own?

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