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Re: possible mDNS issue causing wifi crash?

possible mDNS issue causing wifi crash?

Have C7500 running current firmware V1.01.37 certified for Comcast/Xfinity ISP.

 

Background.  C7500 is used exclusively as wifi router (no hardwired ethernet connections) with only handful of devices that lack 5GHz wifi capability connecting to 2.4GHz radio, all other devices connect to 5GHz radio.  Connecting devices include both static and DHCP-assigned IP addresses, both static and dynamic IPs connect over IPv4 only as well as both IPv4 and IPv6, and both static and dynamic IPs both are perpetually connected as well as connect/disconnect as devices are powered on/off.  C7500 2.4GHz radio is set to least congested non-overlapping channel (e.g., channel 1, 6, or 11) as determined by periodic monitoring using external third-party wifi diagnostic tool.  C7500 is configured to only allow connecting devices by defined MAC address, all others are blocked.

 

Problem.  Since first provisioned on Comcast/Xfinity ISP, C7500 has encountered handful of recurrences in which 2.4GHz radio fails dropping all its connections (5GHz radio remains unaffected) requiring C7500 reboot to restore connections (until next recurrence) -- each recurrence occurring anywhere from several weeks to few months since prior reboot.

 

Have open Netgear support case ongoing now over 8 months with little/no progress.  Granted problem has been difficult to troubleshoot, as failure is intermittent with no discernible pattern and does not appear to log any useful info in C7500 error or event logs.  Netgear support seems intent on me providing them Wireshark logs, but they refuse/unable to explain how Wireshark diagnostic tool running from client would capture useful error info originating from C7500.  Netgear support also refuses/denies existence of SSH/telnet capability into C7500, despite Netgear engineering providing instruction for precisely that on C3700 for troubleshooting unrelated problem with that model that ultimately lead to identifying firmware flaw with that model.

 

Recently happened to see posting on this discussion board (https://community.netgear.com/t5/Orbi-Pro-WiFi-for-Small-Business/Known-Issue-Disconnect-reboot-issu...) in which Netgear has acknowledged mDNS issue that affects its Orbi product.  Looking into mDNS bug exposed by recent known defect with Google Cast, as acknowledged by TP-Link (https://www.tp-link.com/us/support/faq/2050/) and reported to also affect other manufacturers including Netgear, seems mDNS issue can eventually cause router's primary features including wifi connectivity to shut down (rebooting router returns wifi connectivity) -- precisely the behavior am experiencing with C7500.  As trial-and-error test, have configured C7500 to block standard mDNS UDP 5353 port, and interestingly no recurrence yet of same 2.4GHz failure.

 

Netgear support has recently responded that Netgear engineering is refusing to investigate possible mDNS issue with C7500 stating they have no record of other similar reported problems, despite their acknowledged problem with Orbi product.

 

Am hoping to determine if other C7x00 users may be experiencing similar unexplained wifi failure, that may motivate Netgear moderators/admins on this discussion board to advocate to Netgear engineering to investigate possible mDNS issue as being more widespread than they assume and possibly develop firmware fix.

Model: C7500|Nighthawk X4-AC3200 WiFi Cable Modem Router
Message 1 of 6
FURRYe38
Guru

Re: possible mDNS issue causing wifi crash?

What channels are you using? Auto? Try setting manual channel 1, 6 or 11 on 2.4Ghz.
Any Wifi Neighbors near by? If so, how many?

My Setup (Cable 1Gbps/50Mbps)>CM1200 v2.02.03(LAG Disabled)>RBK50 v2.7.2.104(WW)/RBK853 AP Mode v3.2.18.1
Additional NG HW: C7800/CM1100/CAX80/CM2000, Orbi CBK40, R7800, R7960P, EX7500/EX7700, XR450 and WNHDE111
Message 2 of 6

Re: possible mDNS issue causing wifi crash?

FURRYe38 --

 

Thanks for reply.

 

As initially stated, C7500 2.4GHz radio is manually set to least congested non-overlapping channel (e.g., channel 1, 6, or 11) as determined by periodic monitoring using external third-party wifi diagnostic tool.

 

Typically neighboring wifi signals on set channel number less than dozen with only handful of strongest signals with average signal strength never higher than low 40s (on scale of 1-99) -- note happened to have one failure recurrence occur during working hours and had C7500 rebooted shortly thereafter with no wifi issues following reboot, and left another failure recurrence untouched for several days as wifi congestion drops off in middle of the night but to no avail, so doubt issue has anything to do with outside interference.

Model: C7500|Nighthawk X4-AC3200 WiFi Cable Modem Router
Message 3 of 6
FURRYe38
Guru

Re: possible mDNS issue causing wifi crash?

Try turning down the power output of the RBRs wifi radios from 100% to 75 or 50% and see if this changes anything. Under Advanced Tab/Advanced Settings/Wireless Settings

My Setup (Cable 1Gbps/50Mbps)>CM1200 v2.02.03(LAG Disabled)>RBK50 v2.7.2.104(WW)/RBK853 AP Mode v3.2.18.1
Additional NG HW: C7800/CM1100/CAX80/CM2000, Orbi CBK40, R7800, R7960P, EX7500/EX7700, XR450 and WNHDE111
Message 4 of 6

Re: possible mDNS issue causing wifi crash?

FURRYe38 --

 

On C7500 Genie interface, wifi radio power output does not appear to be user-configurable -- see attached screenshot of Advanced tab->Advanced Settings->Wireless Settings page.

 

Am I missing something on configuration of C7500?

Model: C7500|Nighthawk X4-AC3200 WiFi Cable Modem Router
Message 5 of 6
FURRYe38
Guru

Re: possible mDNS issue causing wifi crash?

Well thats a shame. Something that would be helpful here. 

My Setup (Cable 1Gbps/50Mbps)>CM1200 v2.02.03(LAG Disabled)>RBK50 v2.7.2.104(WW)/RBK853 AP Mode v3.2.18.1
Additional NG HW: C7800/CM1100/CAX80/CM2000, Orbi CBK40, R7800, R7960P, EX7500/EX7700, XR450 and WNHDE111
Message 6 of 6
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