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netgear C3700-100NAS sporatic web browsing issues (able to ping / not able to browse).
I have a C3700-100NAS Router/Modem for about 3 months now with comcast as my Internet Service Provider (ISP).
Upon first install around November of 2015, I had issues getting the asset to work appropriately. Unable to load pages, etc. After a factory reset, it seemed to resolve the issue for about 2 or so months. As of around the beginning of January, we have been experiencing issues where Web Pages will not load (firefox/internet explorer/etc), netflix connectivity fails on TV's, etc. Although it seems I am am able to successfully ping 8.8.8.8, google.com, and other sites, web pages seem to sporatically load 20% of the time, and netflix barely works.
Product: Netgear C3700-100NAS
Firmware Version: 2.02.06
ISP: Comcast
Netgear IP: 192.168.1.1
DNS: Auto
DHCP: Enabled
Symptoms: Slow Page Loads, Pages do not load at all, ping works from what I can tell. Adjusted DNS settings from ISP's to Google (8.8.8.8) and no difference. Users experiencing the issue are Wired and Wireless. Platform's are iphones, ipads, tvs, laptops, pcs (no discrimination).
Any help would be greatly appreciated.
In the logs, I do see some follow messages:
- [DoS attack: Teardrop or derivative] from 192.0.104.80, port 0
- [DoS attack: SYN Flood] from 216.241.219.198, port 443
- [DoS attack: TCP- or UDP-based Port Scan] from 75.75.75.75, port 53
In the Event Log, I see some of these errors (last one in November of 2015):
- SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-
Any help would be great!
12 Replies
Have you tried doing a speed test? Try Comcast's and Ookla's to get a couple of data points.
You may also want to look at the traffic statistics on the C3700 and see if your Internet port is saturated. Perhaps those DoS attacks are consuming all of your bandwidth. Did you piss off someone in an online game?
When I can do a speed test, I'm getting about 50-75Mbps download and 15-25Mbps Uploads. Normally, we cannot access the server (it appears the DNS is messed up but changing to google DNS doesn't help).
Since multiple users are experiencing the same issue, it leads me to believe it is the NETGEAR Modem/Router; common denominator.
No. we have not upset anyone in an online game. Nice try... ;)
I'm having the same problems. a temporary fix is to log into your C3700, go to advanced home tab, then on the internet port area, click on connection status. another small window will popup. you can click "renew" to renew your lease. For me it immediately makes the internet work - until the next time which could be hours or minutes.
I'll give that a swagger Eric and see if that helps.
I'm having the EXACT same problem, also using Comcast and same Netgear model. I just started looking at my log yesterday because of other suspicious behaviour I've noticed on personal accounts like banking, gaming, etc.
Releasing, power cycling, renewing, and changing to Google DNS servers did not change my IP address. Here is my most recent log
[DoS attack: SYN Flood] from 152.163.13.6, port 80 1 Sun Jan 24 13:13:02 2016 192.168.0.23:51854 152.163.13.6:80 [DoS attack: SYN Flood] from 69.172.216.111, port 80 1 Sun Jan 24 13:12:19 2016 192.168.0.23:51684 69.172.216.111:80 [DoS attack: SYN Flood] from 74.119.118.94, port 80 1 Sun Jan 24 13:12:13 2016 192.168.0.23:51669 74.119.118.94:80 [DoS attack: SYN Flood] from 69.194.244.11, port 80 1 Sun Jan 24 13:12:09 2016 192.168.0.23:51640 69.194.244.11:80 [DoS attack: SYN Flood] from 173.241.250.221, port 80 1 Sun Jan 24 13:11:52 2016 192.168.0.23:51505 173.241.250.221:80 [DoS attack: SYN Flood] from 184.25.254.64, port 80 1 Sun Jan 24 13:11:05 2016 192.168.0.23:51381 184.25.254.64:80 [DoS attack: SYN Flood] from 69.194.244.11, port 443 1 Sun Jan 24 13:10:55 2016 192.168.0.23:51351 69.194.244.11:443
[DoS attack: TCP- or UDP-based Port Scan] from 75.75.75.75, port 53 1 Sun Jan 24 12:55:47 2016 73.71.107.103:55949 75.75.75.75:53 Ping has also been disabled since installation, which was about 8 months ago. I'm beginning to think there's a vulnerability in the router Netgear is unaware of or unable to address. Any other suggestions would be great.
Thanks
C7000 here. Similar issues.
I notice if I change DNS to 8.8.8.8 then it feels it's being DoS'd by 8.8.8.8 and if I leave it at Comcast's default of 75.75.75.75 then the router thinks it's being DoS'd by 75.75.75.75.
It's probably okay to "Disable Port Scan and DoS Protection" as suggested. We have no way to know what this feature even does but can assume from the logs that it's kind of dumb.
- Im happy to hear I'm not the only one! After disabling that feature several months ago, there haven't been any complaints from my friends who use it. I'm hopeful that NETGEAR will release a firmware update to remedy soon.
Thanks for responding!
