Re: RBR850 frequently issuing DNS REFUSED responses

amenic · ‎2020-09-19

How do you disable it after enabling it? I notice that it's available outside network (WAN).

Retired_Member · ‎2020-09-20

I guess you could set the

telnetd_enable=1 to 0 and do a nvram commit and reboot

FURRYe38 · ‎2020-09-20

https://community.netgear.com/t5/Orbi-AX/Intermittent-DNS-lookup-failures-on-RBR850/td-p/1978111/jum...

@Retired_Member wrote:
I guess you could set the
telnetd_enable=1 to 0 and do a nvram commit and reboot

Retired_Member · ‎2020-09-21

I have inspected a litle further and with strace you could see tons of errormessages regarding read like this:

read(8, 0x166feda0, 272) = -1 EAGAIN (Resource temporarily unavailable)

where fd=8 is coming from the following call:

inotify_add_watch(8, "/tmp", IN_CLOSE_WRITE|IN_MOVED_TO) = 1

I guess the idea here was to watch for changes in resolve.conf and this might be a bug.

A lot of daemons logs to /tmp and making dnsmasq busy watching filecloses in /tmp

which result in the DNS forward request being "refused"

A workaround that seems to do the trick is to move resolv.conf to a less busy directory, in my case I created /tmp/dns/resolve.conf

and launched from commandline:

/usr/sbin/dnsmasq -h -n -c 0 -N -i br* -r /tmp/dns/resolv.conf -u root

No dns-errors after 1 hour running so fare

Ace321 · ‎2020-09-22

@Retired_Member @FURRYe38 Looks like you have signed up to be beta testers. As few of us are having these DNS issue, can you please forward the issue and above resolution to NG engineering? Hopefully they will take that into condieration in next foirmware update.

Thanks!

Retired_Member · ‎2020-09-22

Running without errors for 24 hours now, so this seems to have fixed it.

I will send the information to them, and request for a bugfix. Propably is the "-n" --no-poll feature broken and the file-poll badly implementet.

FURRYe38 · ‎2020-09-22

Any forum user experiencing problems with there NG products are encouraged to first and foremost make contact with NG support:

https://www.netgear.com/support/#

File a support ticket and let NG know about what you are experiencing. You can also try contacting a forum moderator as well. Blanca_O, and Christian_R, ErnestTheGreat are my first moderators I try to contact.

Thank you.

@Ace321 wrote:
Looks like you have signed up to be beta testers. As few of us are having these DNS issue, can you please forward the issue and above resolution to NG engineering? Hopefully they will take that into condieration in next foirmware update.

Thanks!

amenic · ‎2020-09-22

Still learning the implementation so far it looks like they run this software based on openwrt and everything is loaded into RAM (tmpfs) at boot from the image. Which means you can't make persistent changes to the filesystem once loaded.

So, all if you have to do is reboot to revert changes made which is what I did to undo Telnet access.

Retired_Member · ‎2020-09-22

This is not correct, you could do a lot of changes which will remain after reboot.

nvram, overlay-filesystem ant more will not be erased.

/tmp is tmpfs and cleared each time

amenic · ‎2020-09-23

@Retired_Member wrote:
This is not correct, you could do a lot of changes which will remain after reboot.

nvram, overlay-filesystem ant more will not be erased.

/tmp is tmpfs and cleared each time

Well that's good news - can you please walk me through how I can modify the parameters dnsmasq uses so that they persist each boot?

Cheer!

Retired_Member · ‎2020-09-23

Something like this will do:

copy /usr/sbin/dnsmasq to /overlay/upper/usr/sbin/orbi-dnsmasq

make a file called dnsmasq in /overlay/upper/usr/sbin (this will hide the original dnsmasq from the running os) with the following lines:

#!/bin/sh
mkdir /tmp/dns
echo "nameserver 8.8.8.8" > /tmp/dns/resolv.conf
echo "nameserver 8.8.4.4" >> /tmp/dns/resolv.conf
/usr/sbin/orbi-dnsmasq -h -n -c 0 -N -i br* -r /tmp/dns/resolv.conf -u root

jj911c2 · ‎2020-09-25

Thank you for posting these instructions. I have been working with Netgear support but they jsut suggested I return the device to the store vs troubleshooting.

I enabled telnet on the Orib and connected via the Windows built in telnet client. When I try to run the first line I get an error saying "copy: not found"

root@RBR750:/tmp/dns#
root@RBR750:/tmp/dns# copy /usr/sbin/dnsmasq to /overlay/upper/usr/sbin/orbi-dns
masq
/bin/ash: copy: not found

Am I missing a step?

Ace321 · ‎2020-09-25

You have to use Linux commands I believe. For example "CP" for Copy function.

Ace321 · ‎2020-09-25

May be @Retired_Member can write exact commands to execute.

Retired_Member · ‎2020-09-25

Yes I could do that, but I see there is a big risk for people to brick their Orbi-routers when not used to work on unix-systems.

And I would not be responsible for this, as my guide could may be missread or badly written by me 🙂

I have reported the bug found in dnsmasq and I hope Netgear will work on this and make a patch for everyone to install.

Mikey94025 · ‎2020-09-25

If you are using Windows, the easy and safe workaround is to set the DNS settings for your network connection to go directly to the DNS server IP address instead of through the Orbi. This workaround worked for me on my Windows laptop and eliminated the intermittent DNS failures. I used google DNS 8.8.8.8 but you can substitute your ISP's DNS address instead.

Hit the Windows key and search for "control panel"
Network and Internet
Network and Sharing Center
On the left, Change Adapter Settings
For each wi-fi or other network adapter used, right-click and select Properties
Select Internet Protocol Version 4 (TCP/IPv4) in the list and press Properties
The second checknox is set to Obtain DNS Server Address Automatically. Change it to Use The Following DNS Server Addresses
Enter 8.8.8.8 and 8.8.4.4 (the Google DNS addresses)
Press OK

Now it should bypass the Orbi for DNS and go straight to the DNS servers.

scng · ‎2020-10-18

Same problem with RBR750.

@Retired_Member wrote:
Yes I could do that, but I see there is a big risk for people to brick their Orbi-routers when not used to work on unix-systems.
And I would not be responsible for this, as my guide could may be missread or badly written by me 🙂

I have reported the bug found in dnsmasq and I hope Netgear will work on this and make a patch for everyone to install.

jj911c2 · ‎2020-10-18

I had the same problems w/ my 750 and tried all the troubleshooting steps as well as opening a support case with Netgear. I was unable to fix the issue with DNS.

I ended up just flipping my cable modem (Xfinity) back to router mode and set the Orbi to AP mode. You really don't lose a lot of functionality (I can still see which devices are connected to each satellite in the Orbi application) in AP mode. This fixes the DNS issue as your cable modem takes over this functionality. Strange you have to do this for such a high end system...but the signal strength/wired satellites makes it worth keeping.

wonky · ‎2020-11-03

Hi, I'm having this same problem, and am using the "workaround" for my Windows computer (bypassing the router's DNS service). I directed NG support to this forum thread so they could understand the problem. I asked for a projected resolution date for this bug, but cannot seem to get an answer. When you shared this problem with NG engineering, did they give any indication of where this bug is prioritized in their backlog? Thank you for digging into this problem!

jj911c2 · ‎2020-11-03

I did not make any progress with my support case.

If you can, flip your ISP modem back to router mode and set your Orbi to AP mode. This completely fixed the issue for me for all devices.

Capt_Hellcat · ‎2020-11-06

5 months since this thread started and no resolution? just a workaround that only works for devices i can manually set DNS on? At least i know im not alone in this and was wondering what was the cause of all my random DNS issues. i suspected it was the router since its new but i did just move and while still google fiber, it is a new location. guess its the router. if i didnt need the coverage these 3 orbi's give, i'd go back to my trusty asus ax88u and merlin firmware

FURRYe38 · ‎2020-11-06

What Firmware version is currently loaded?
What is the Mfr and model# of the Internet Service Providers modem/ONT the NG router is connected too?

Whos your provider?

Has a factory reset and setup from scratch been performed since last FW update?

I'm on Sparklith and using a CAX80 in modem mode and RBR850 in router mode and have not seen any problems in this regard...

@Capt_Hellcat wrote:
5 months since this thread started and no resolution? just a workaround that only works for devices i can manually set DNS on? At least i know im not alone in this and was wondering what was the cause of all my random DNS issues. i suspected it was the router since its new but i did just move and while still google fiber, it is a new location. guess its the router. if i didnt need the coverage these 3 orbi's give, i'd go back to my trusty asus ax88u and merlin firmware

wonky · ‎2020-11-08

@FURRYe38, for what it’s worth, I have: Xfinity with a MB7621 cable modem, with the latest NG firmware (as of 11/6/20) on the Orbi ax 4200. I also have a support case open. The workaround of bypassing this router’s DNS resolution works for my Windows PCs. It also works to replace the router function altogether with a different router, but that defeats the purpose of buying this. I’ve had both my old ASUS and Google routers working with this modem/ISP and it works fine. @Retired_Member has identified the bug, so it’s pretty frustrating that we can’t get a projected resolution date from NG support. If you have influence with NG, it would be great if we at least got a projected date for a bug fix.

Ace321 · ‎2020-11-08

@wonky I have similar experience with NG support. Exhanged lot of emails, sent logs, phone calls with them. Finally NG support told me that they have forward to their engineering team. After that, all communication died from NG with no updates. Few days later, I received a pm from moderator of this thread. She (Bianca I beleive) was very helfull and pushed my ticket with NG support. NG support person (Sophia) called me right away who was working on my case earlier. I was in a meeting and missed her call. I informed her and even setup a time with her to talk. She claimed that she needs more information from me. She never called me during that scheduled time. Since then I am still waiting for a call from NG. Bottom line, NG is somehow refusing to acknowledge this issue.

wwxxyyzz · ‎2020-12-06

I'm also seeing this on a RBK752/RBR750. Wired connection to PC and wireless to other devices. Webpass is my ISP. IPv6 disabled on the router. Latest firmware. Factory reset of the router. Still fails. All of my devices fail to make connections on a daily basis.

How is this not fixed after several months?