<SOLVED ITSELF> Modem connected to router drops connection

[WharfRat]

I've been using a Netgear CM600 modem with a Linksys WRT1900AC router for about a year with no problems.

Suddenly the Ethernet WAN connection started dropping intermittently and inxi -i reports WAN IP: IP Source Corrupt.

I checked the other computer connected to the router and the symptom was the same.

My first thought was my service provider, but they said everything was OK on their end.

I connected a computer directly to the modem and sure enough it stayed connected.

I reset the router to no avail and, just for kicks, re-flashed the firmware; still dropping the connection.

I pulled out an old 10/100 wireless router and the same thing happened - corrupt source.

So I reset the modem, reconnected the WRT1900AC router and modem and it's still dropping the connection.

I'm completely baffled and wondering if any one else here had a similar experience and was able to solve it.

Thanks...

[Cosmo.]

Quick shot: Did you try another cable between modem and router?

[WharfRat]

Quick shot: Did you try another cable between modem and router?

Yep, tried two cables - one was the new one that came with the modem.

I can only get online when connected directly to the modem,

I tried a wireless connection and got the same thing.

[Pippin]

Disabled firewall?

[WharfRat]

Disabled firewall?

This is it

Code: Select all

[bill@XPS] ~ $ sudo iptables -S
-P INPUT ACCEPT
-P FORWARD ACCEPT
-P OUTPUT ACCEPT
[bill@XPS] ~ $ 

I placed inxi -i|grep -i wan;sleep 3 in a loop and this is the result - I replaced the IP address with xx.xx.xx.xx

Code: Select all

WAN IP: None Detected! IF: enp0s31f6 ip-v4: N/A
WAN IP: xx.xx.xx.xx IF: enp0s31f6 ip-v4: 192.168.1.168
WAN IP: xx.xx.xx.xx IF: enp0s31f6 ip-v4: 192.168.1.168
WAN IP: xx.xx.xx.xx IF: enp0s31f6 ip-v4: 192.168.1.168
WAN IP: xx.xx.xx.xx IF: enp0s31f6 ip-v4: 192.168.1.168
WAN IP: xx.xx.xx.xx IF: enp0s31f6 ip-v4: 192.168.1.168
WAN IP: IP Source Corrupt! IF: enp0s31f6 ip-v4: 192.168.1.168
WAN IP: IP Source Corrupt! IF: enp0s31f6 ip-v4: 192.168.1.168
WAN IP: IP Source Corrupt! IF: enp0s31f6 ip-v4: 192.168.1.168
WAN IP: IP Source Corrupt! IF: enp0s31f6 ip-v4: 192.168.1.168
WAN IP: IP Source Corrupt! IF: enp0s31f6 ip-v4: 192.168.1.168
WAN IP: IP Source Corrupt! IF: enp0s31f6 ip-v4: 192.168.1.168
WAN IP: IP Source Corrupt! IF: enp0s31f6 ip-v4: 192.168.1.168
WAN IP: IP Source Corrupt! IF: enp0s31f6 ip-v4: 192.168.1.168
WAN IP: xx.xx.xx.xx IF: enp0s31f6 ip-v4: 192.168.1.168
WAN IP: xx.xx.xx.xx IF: enp0s31f6 ip-v4: 192.168.1.168
WAN IP: IP Source Corrupt! IF: enp0s31f6 ip-v4: 192.168.1.168
WAN IP: IP Source Corrupt! IF: enp0s31f6 ip-v4: 192.168.1.168
WAN IP: IP Source Corrupt! IF: enp0s31f6 ip-v4: 192.168.1.168
WAN IP: IP Source Corrupt! IF: enp0s31f6 ip-v4: 192.168.1.168
WAN IP: IP Source Corrupt! IF: enp0s31f6 ip-v4: 192.168.1.168
WAN IP: IP Source Corrupt! IF: enp0s31f6 ip-v4: 192.168.1.168
WAN IP: IP Source Corrupt! IF: enp0s31f6 ip-v4: 192.168.1.168
WAN IP: IP Source Corrupt! IF: enp0s31f6 ip-v4: 192.168.1.168
WAN IP: IP Source Corrupt! IF: enp0s31f6 ip-v4: 192.168.1.168
WAN IP: IP Source Corrupt! IF: enp0s31f6 ip-v4: 192.168.1.168
WAN IP: IP Source Corrupt! IF: enp0s31f6 ip-v4: 192.168.1.168
WAN IP: xx.xx.xx.xx IF: enp0s31f6 ip-v4: 192.168.1.168
WAN IP: xx.xx.xx.xx IF: enp0s31f6 ip-v4: 192.168.1.168
WAN IP: xx.xx.xx.xx IF: enp0s31f6 ip-v4: 192.168.1.168
WAN IP: xx.xx.xx.xx IF: enp0s31f6 ip-v4: 192.168.1.168
WAN IP: xx.xx.xx.xx IF: enp0s31f6 ip-v4: 192.168.1.168
WAN IP: xx.xx.xx.xx IF: enp0s31f6 ip-v4: 192.168.1.168
WAN IP: IP Source Corrupt! IF: enp0s31f6 ip-v4: 192.168.1.168
WAN IP: IP Source Corrupt! IF: enp0s31f6 ip-v4: 192.168.1.168
WAN IP: IP Source Corrupt! IF: enp0s31f6 ip-v4: 192.168.1.168
WAN IP: IP Source Corrupt! IF: enp0s31f6 ip-v4: 192.168.1.168
WAN IP: IP Source Corrupt! IF: enp0s31f6 ip-v4: 192.168.1.168
WAN IP: IP Source Corrupt! IF: enp0s31f6 ip-v4: 192.168.1.168
WAN IP: IP Source Corrupt! IF: enp0s31f6 ip-v4: 192.168.1.168
WAN IP: IP Source Corrupt! IF: enp0s31f6 ip-v4: 192.168.1.168
WAN IP: IP Source Corrupt! IF: enp0s31f6 ip-v4: 192.168.1.168
WAN IP: IP Source Corrupt! IF: enp0s31f6 ip-v4: 192.168.1.168
WAN IP: IP Source Corrupt! IF: enp0s31f6 ip-v4: 192.168.1.168
WAN IP: xx.xx.xx.xx IF: enp0s31f6 ip-v4: 192.168.1.168
WAN IP: xx.xx.xx.xx IF: enp0s31f6 ip-v4: 192.168.1.168
WAN IP: xx.xx.xx.xx IF: enp0s31f6 ip-v4: 192.168.1.168
WAN IP: xx.xx.xx.xx IF: enp0s31f6 ip-v4: 192.168.1.168
WAN IP: xx.xx.xx.xx IF: enp0s31f6 ip-v4: 192.168.1.168
WAN IP: xx.xx.xx.xx IF: enp0s31f6 ip-v4: 192.168.1.168
WAN IP: xx.xx.xx.xx IF: enp0s31f6 ip-v4: 192.168.1.168
WAN IP: xx.xx.xx.xx IF: enp0s31f6 ip-v4: 192.168.1.168
WAN IP: IP Source Corrupt! IF: enp0s31f6 ip-v4: 192.168.1.168

The first line is when the the network manager was not enabled.

It just keeps dropping and reestablishing the connection.

[Cosmo.]

There are not so many devices in game. 2 of them - modem and computer - do obviously work, as demonstrated with the direct connection. This places the suspicion to the router.

You have exchanged the router with on old device. But is this really supposed to work?
I give you an example for my question: Until about 18 months back I had a rather low-end dsl connection with a good working modem and router. When I got my current V-DSL connection, modem and router had to get replaced, the old devices would never work with V-DSL. If I would now encounter your problem and would for testing replace my new router with the old one (from which I know, that it worked until the last day with DSL), it would never work and would not been assumed to work.

From this example I wonder, if your old router has perhaps the same limitation as my old router. If this should be the case, the failing connection with the old router would be expected and it would not say anything about the status of the new router.

Long story short: Is there a chance to replace your Linksys with a lent out device? Or to take the Linksys to a friend and replace his router with yours?

[Pippin]

Firewall open, cables seem ok, hmm.

Computers both running same version Mint/kernel?
Tried other kernel?
Tried other OS?

[WharfRat]

Cosmo.,

You have a good suggestion trying the router at another location.

Just for clarification the old router was working flawlessly with the same ISP I have now.

The reason I replaced it was because it was only 10/100 so I figured it was long overdue for an upgrade.

I'm not adverse to replacing either or both components, but when swapping routers makes no difference and the modem running uninterrupted connected directly to the
computer it isn't clear if replacing them would make any difference.

These symptoms started very late last evening and I wrote it off as a temporary IPS issue.

Just very puzzling indeed

[asinoro]

Any difference from live usb, dvd?

[greerd]

You should be able to confirm what your ISP says about the Netgear, see this site for more info. Basically connect direct to your Netgear and enter http://192.168.100.1. The downstream cable levels should be between +/- 7dBmV while the upstream should be somewhere in the 38 - 48 dBmV.

[DAMIEN1307]

hi wharfrat...dont count out an ISP problem just yet...about a year ago, i had a similar problem...my main computer would work when plugged directly into modem but not into the router...the ISP did its usual from there end and pronounced my router as dead...i knew that wasnt true because what i did next was to enter the code for the modem and looked for its snr...(signal to noise ratio)...its supposed to be anywhere from around 38db to 40db thereabouts...well wouldnt you know that it was anything but...that got them to pay a personal visit along with a new modem and a guy climbing the pole to find a bad, weathered wiring problem on the pole...problem solved...see what your signal to noise ratio is on your modem just to be sure...DAMIEN

heres mine in good working order...

DCID Freq Power SNR Modulation Octets
Downstream 1 3 243.00 MHz 8.43 dBmV 40.37 dB 256QAM 18412192313
Downstream 2 1 231.00 MHz 9.04 dBmV 40.95 dB 256QAM 16468615236
Downstream 3 2 237.00 MHz 8.75 dBmV 39.85 dB 256QAM 16280808468
Downstream 4 5 255.00 MHz 7.77 dBmV 40.37 dB 256QAM 15342307881
Downstream 5 7 267.00 MHz 7.08 dBmV 40.37 dB 256QAM 15708708264
Downstream 6 8 273.00 MHz 6.79 dBmV 40.37 dB 256QAM 14615855152
Downstream 7 9 279.00 MHz 6.96 dBmV 40.95 dB 256QAM 16836671009
Downstream 8 10 285.00 MHz 6.73 dBmV 40.37 dB 256QAM 17380647367
Reset FEC Counters
Upstream
UCID Freq Power Channel Type Symbol Rate Modulation
Upstream 1 3 35.30 MHz 38.50 dBmV DOCSIS2.0 (ATDMA) 5120 kSym/s 64QAM
Upstream 2 1 21.50 MHz 36.75 dBmV DOCSIS2.0 (ATDMA) 5120 kSym/s 64QAM
Upstream 3 2 28.40 MHz 37.25 dBmV DOCSIS2.0 (ATDMA) 5120 kSym/s 64QAM

hope this is helpful

[Cosmo.]

Just to make it clear: When I switched from dsl to v-dsl I stayed at the same ISP. So having the same ISP does not say anything. The question would be, if the type of connection has been changed, since you have the new router. If this should be the case, it would be possible - but not necessary -, that the old router can no longer connect.

My other point is this: At any point there must be the culprit. There are only 3 possible points. Modem and computer seem to be fine. That means, that from reversing conclusion only the router leaves as culprit.

Or in difference to what your ISP told you there is an issue with their connection. (I have learned in all those years, that they sometimes tell all but the truth. I also made the experience - more than once - that if I call 2 or more times because of the same problem I had, I got (from different support people) different answers.) So you might also try to call them again or try to search in the web, if there are other people with your problem.

[WharfRat]

@asinoro

Haven't tried any other media since two ethernet connected and one wireless experience the same symptoms.

@greerd

I'm not a ISP expert so how does this look to you

Code: Select all

Startup Procedure
Procedure 	Status 	Comment
Acquire Downstream Channel 	609000000 Hz 	Locked
Connectivity State 	OK 	Operational
Boot State 	OK 	Operational
Security 	Enable 	BPI+
IP Provisioning Mode 	Honor MDD 	IPv4 only
 
Downstream Bonded Channels
Channel 	Lock Status 	Modulation 	Channel ID 	Frequency 	Power 	SNR 	Correctables 	Uncorrectables
1	Locked	QAM256	6	609000000 Hz	5.3 dBmV	41.0 dB	0	0
2	Locked	QAM256	1	567000000 Hz	5.7 dBmV	41.7 dB	0	0
3	Locked	QAM256	2	573000000 Hz	5.6 dBmV	41.6 dB	0	0
4	Locked	QAM256	3	579000000 Hz	5.5 dBmV	41.6 dB	0	0
5	Locked	QAM256	4	585000000 Hz	5.7 dBmV	41.4 dB	0	0
6	Locked	QAM256	5	603000000 Hz	5.3 dBmV	41.1 dB	0	0
7	Locked	QAM256	7	615000000 Hz	5.4 dBmV	40.9 dB	0	0
8	Locked	QAM256	8	621000000 Hz	5.4 dBmV	40.9 dB	0	0
9	Locked	QAM256	9	627000000 Hz	4.9 dBmV	40.4 dB	0	0
10	Locked	QAM256	10	633000000 Hz	5.5 dBmV	40.8 dB	0	0
11	Locked	QAM256	11	639000000 Hz	5.3 dBmV	40.6 dB	0	0
12	Locked	QAM256	12	645000000 Hz	5.7 dBmV	41.0 dB	0	0
13	Locked	QAM256	13	651000000 Hz	5.3 dBmV	40.5 dB	0	0
14	Locked	QAM256	14	657000000 Hz	5.2 dBmV	40.5 dB	0	0
15	Locked	QAM256	15	663000000 Hz	5.0 dBmV	40.3 dB	0	0
16	Locked	QAM256	16	669000000 Hz	5.2 dBmV	40.3 dB	0	0
17	Locked	QAM256	17	675000000 Hz	5.2 dBmV	40.9 dB	0	0
18	Locked	QAM256	18	681000000 Hz	5.1 dBmV	40.8 dB	0	0
19	Locked	QAM256	19	687000000 Hz	4.9 dBmV	40.8 dB	0	0
20	Locked	QAM256	20	693000000 Hz	5.3 dBmV	41.4 dB	0	0
21	Locked	QAM256	21	699000000 Hz	5.4 dBmV	41.1 dB	0	0
22	Locked	QAM256	22	705000000 Hz	5.3 dBmV	40.9 dB	0	0
23	Locked	QAM256	23	711000000 Hz	4.7 dBmV	40.7 dB	0	0
24	Locked	QAM256	24	717000000 Hz	4.7 dBmV	40.4 dB	0	0
 
Upstream Bonded Channels
Channel 	Lock Status 	US Channel Type 	Channel ID 	Symbol Rate 	Frequency 	Power
1	Locked	ATDMA	1	5120 Ksym/sec	35000000 Hz	47.8 dBmV
2	Locked	ATDMA	2	5120 Ksym/sec	28400000 Hz	48.3 dBmV
3	Locked	ATDMA	3	5120 Ksym/sec	22000000 Hz	48.5 dBmV
4	Locked	ATDMA	4	5120 Ksym/sec	14000000 Hz	48.0 dBmV
 
Current System Time: Tue Apr 17 15:04:23 2018
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[DAMIEN1307]

i see that the snr...(signal to noise ratio) is blank...as well as the corrected and uncorrectables being blank as well...DAMIEN

[WharfRat]

i see that the snr...(signal to noise ratio) is blank...as well as the corrected and uncorrectables being blank as well...DAMIEN

I think it's just the cut and paste formatting. Here's a screen shot.

NETGEAR Gateway CM6002.jpg

The uncorrectables are all 0 too.

[WharfRat]

Firewall open, cables seem ok, hmm.

Computers both running same version Mint/kernel?
Tried other kernel?
Tried other OS?

This machine is running 4.4.0-119-generic and the other which I just did a clean install over the weekend is at 4.13.0-38.

Is there another OS besides Linux

[greerd]

@greerd

I'm not a ISP expert so how does this look to you

I'm no expert myself, but those levels look good to me.

[DAMIEN1307]

ok...the snr looks ok to me thus far...something else to maybe look at...are you on a static or dynamic WAN connection type?...if anything has changed with your ISP lately, it would have also possibly changed your IP. address..if you were on static, rather than dynamic, then your router will not respond to the change...that control would be found in your router not the modem...DAMIEN

[WharfRat]

@greerd

I'm not a ISP expert so how does this look to you

I'm no expert myself, but those levels look good to me.

I thought they looked good too, but another evaluation is reassuring.

[greerd]

Are you running stock firmware on the WRT1900 or something like OpenWRT/LEDE ? Either way you should be able to ping the Netgear directly from the WRT, I think its in the trouble shooting section of the stock firmware.

Also, can you communicate with another computer, both connected to the WRT switch?