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Reading, PA

Odd wireless problem WNDR3700

Hi all..

Have a problem with a router, trying to track down if this is a router issue or ISP issue.

I have a WNDR3700v3 connected to an Arris TM722G with Comcast. The CM does both voice and Internet. The router I believe has the latest firmware, V1.0.0.22_1.0.17, at least I could not find a newer version.

Anyway the problem is this: randomly and very often, like every day or every other day, all wireless connections lose Internet connectivity. The wireless connections on every device are still good, that is they have a strong connection. It's just that they lose the inability to use the Internet. When this is happening I can disconnect and reconnect the wireless just fine, but still cannot access the Internet.

I had the exact issue before using the Netgear WNR3500L that I received from SamKnows, in fact I bought this router while waiting for them to send a replacement which they did (two actually).

I also have the SamKnows 3500 connected up on the 3rd floor, it's connected to the 3700 via ethernet and running in Bridged Mode. The loss of Internet access happens also to any wireless device connected to the 3500.

Thinking there might be a conflict, first I disconnected and powered off the router on the 3rd floor, no luck, still lost Internet connectivity even with the 3500 disconnected and powered off. Next was to get a WiFi analyzer - using an Android app called appropriately enough, WiFi Analyzer - this app showed me that of the 8-12 other wireless routers in range, all but one are using the default channel 6. This app also shows which channels are "better" (stronger?).. As luck would have it, channels 10 and 11 were pegging the scale and no device in range is using them - So I have the 3700 running on channel 11, and the 3500 on channel 10.

Still no luck, less than 12 hours from setting the channels, and doing a full power-cycle of everything, it happens again.. All wireless connections lose Internet connectivity.. again the wireless connection is still active and strong - there is no problem connecting to any device on the internal network, for example I can print from my laptop to the main printer, both are on wireless - they just lose all Internet connectivity.

The only solution is to either reboot or power-cycle the 3700 router.

This has been going on since last May, when we switched to Comcast's VOIP, thus adding the Arris MTA. Up until this month the wireless problem happened maybe once or twice a month.. Now it's happening 2, 3, 4 times a week. Finally, when this does happen, all the wired devices connect out to the Internet just fine.


- Got Comcast VIOP last year
- Wireless devices lose Internet connectivity at random
- only fix is a reboot

I'm not sure now where the problem is. Is it strictly a router problem? Could it be some sort of incompatibility between Netgear and the Arris MTA? While it happened rarely in the past why now is it happening just about every day?

Any help would be appreciated.


Marietta, GA

OK, so if it's happening with two different routers then usually you can rule them out (look for the single point of failure). Do you have a different router you can test with? You say it fails accessing the internet, but have you tried some ping tests or DNS lookups? It may be some kind of DNS failure to the wireless clients? Is there any kind of MAC blocking\filtering going on? This sounds like an interesting problem!

Reading, PA

ping tests fail out past the router.. using my laptop wireless when this happens I am able to ping the router's gateway IP and the IPs of all other devices connected to the router, wired or wireless..

DNS lookups, using nslookup, when using Comcast or another external DNS server will fail - usually server fail due to it being unreachable. DNS lookups come back fine using my (wired) server which runs BIND, but since they are external of the router, attempts to connect fail due to the site being unreachable..

traceroutes reach my router's gateway address but go no further..

There is no MAC blocking or filtering going on. I even tried giving some of my wireless devices static IPs to bypass the DHCP server with no luck.

Let's see what else, QOS is turned off, I also disabled ipv6 to rule out any conflict there. Nothing seems to make a difference.

I do have a spare router.. another WNR3500L that I got from SamKnows - sitting unopened.. I suppose I could disable the SK logging and try that out, or maybe if I can figure out what version it is, load dd-wrt or tomato on it..


Henderson, NV
reply to beerbum

I have the same problem with the WNR3500L. In fact I have two of these routers and it happens on both. My wireless connection disappears once a day when the DHCP lease is renewed. It will reconnect by itself in ten minutes or less on all wireless devices.

This problem started after I connected a USB drive to the router.

The same problem occurs when using Tomato except the wireless devices reconnect within two minutes.