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Re: DGND3700V2 refuses to restore from any saved settings files

Sec_Engineer
Tutor

DGND3700V2 refuses to restore from any saved settings files

I have 3 DGND3700V2 Routers running the latest firmware upgrade [FW Version V1.1.00.26_1.00.26NA]  that I have been trying to restore from a saved settings file.

I cannot restore the settings in any fashion, even after using the "Restore Factor Settings" reset button. I am connected via the www.routerlogin.net URL.

I am using Firefox 103.0.2 (64-bit) as my browser. It has failed with lesser revisions as well.

I have tried the Microsoft Edge 104.0.1293.63 (64-Bit) browser with the same results.

I am on a known good power supply, connected to the same Windows 10 PC that received the setting from the initial backup.

It is connected to that PC by a single Ethernet cable and connected to no other networks, nor ADSL connections. All indicators are green except for the 5Ghz which is blue.

In every attempt I get the "Restore failure!" message

I have searched the Internet, and this community, for any clues, assuming I must be doing something wrong. All I find are the skeletons of others who have not been able to solve the mystery.

 

Is there any chance that someone has found the solution and is willing to share it? As I noted I have 3 routers than need to be cloned from the saved settings for backup and disaster recovery purposes. I am hopeful someone will come forward and reveal the solution.

 

Thanks for your time, one and all...!!! It is sincerely appreciated.

 

 

Message 1 of 7

Re: DGND3700V2 refuses to restore from any saved settings files


@Sec_Engineer wrote:

I have 3 DGND3700V2 Routers running the latest firmware upgrade [FW Version V1.1.00.26_1.00.26NA]  that I have been trying to restore from a saved settings file.

 


Does the saved settings file come from one of these three modem/routers?

 

Are they all the V2 hardware versions? V1 settings will not work on V2 firmware.

 

Do these devices work as expected when they are reset.

 


I am using Firefox 103.0.2 (64-bit) as my browser. It has failed with lesser revisions as well.

I have tried the Microsoft Edge 104.0.1293.63 (64-Bit) browser with the same results.

 


It is a  bit puzzling that you talk about this. Browsers have next to nothing to do with the process. If it works with one browser it will work with all browsers. The browser is just your way into the router's graphical user interface (GUI).

 

Does that work? Can you get to the appropriate Restore Configuration Settings page?

 

Note that there hasn't been a firmware update since 2016. (This is an old model that dates back to 2011.) There can be firmware updates that change the underlying firmware in ways that are not compatible with what went before. I doubt if that is the case here, but it has happened. You might be able to restore to older firmware, but not to this one.

 

Finally, it just might be that the saved settings file is broke.

 

 

Message 2 of 7
Sec_Engineer
Tutor

Re: DGND3700V2 refuses to restore from any saved settings files

Does the saved settings file come from one of these three modem/routers? Yes

 

Are they all the V2 hardware versions? V1 settings will not work on V2 firmware Yes, all three are  V2 hardware. And I know they are old hardware, but they have been rock solid thus far and work great for my application.

 

Do these devices work as expected when they are reset. Yes, when reset to factory, and have gone through the initial config they work as expected. I'm trying to clone 2 of them to match the one currently in operation, as I have a number of special settings in the Port Forwarding section for my specific application to support remote access of devices behind the router.

 

It is a  bit puzzling that you talk about this. Browsers have next to nothing to do with the process. If it works with one browser it will work with all browsers. The browser is just your way into the router's graphical user interface (GUI). Just trying to be complete in my description, in case the Genie .html code implementation on these routers might be sensitive in some way to later browsers in terms on .html language advancements over the years. And also to reduce the opportunity to get cautioned for not providing enough detail. I figured if I didn't provide it, someone would likely ask.

 

Does that work? Can you get to the appropriate Restore Configuration Settings page? Yes. Accessing the function works just fine. It's how I made the .cfg file to start with. In fact, I created .cfg files from all 3 routers, and no matter which one I use, none of the two devices I'm making as clones will restore the settings and thus produce the same error. Basically, I have one running, from which I took the initial backup, the remaining two were firmware upgraded to the latest firmware available to match that of the "master" router, and then I attempted to restore from the "master" .cfg file.

 

Note that there hasn't been a firmware update since 2016. (This is an old model that dates back to 2011.) There can be firmware updates that change the underlying firmware in ways that are not compatible with what went before. I doubt if that is the case here, but it has happened. You might be able to restore to older firmware, but not to this one. The firmware I installed was downloaded directly from the Netgear site. I have an expectation that firmware they provide on their own site should have been tested and any "incompatibilities" noted. It's been a seamless process in the past. And if the condition did indeed exist and you noted, I would expect the restoration process to have noted something like "Bad parameter found,,, aborting" rather than just saying "Restore failure!".  Simply punting is not a sane option, IMHO.

 

Finally, it just might be that the saved settings file is broke. Really? All three seem to match in format. I plan to take them to one of my Linux systems shortly to run a diff on them to see if anything stands out. From a cursory viewing, they all seem to be identical. The diff program, however,  will ultimately tell  the true story. And if the device running the most recent firmware can't generate a setting file it can read back correctly, well that would seem to be a serious product issue. That said, I have downloaded the GPL code sources for this firmware version to see if I can look at that specific function to see how it actually works and what the "restore" function is actually looking at when it throws up its hands and declares "Restore failure!".  It will be an interesting journey indeed.

 

Thanks for your time to respond. If you have any ideas, I'd appreciate you sharing them. Have a great day!

Message 3 of 7
Sec_Engineer
Tutor

Re: DGND3700V2 refuses to restore from any saved settings files

08/24/2022 Update:

I actually have 3 of these DGND3700V2 routers. Router 1 is currently in service, but lacking all the parameter settings needed to access my devices in a remote location 2 hours away. It was put in service following a power supply failure. Router 2 is the unit that was replaced and holds all the necessary settings and whose .cfg  files I need to get into Router 1 and Router 3 which has had its firmware updated to match Router 1 and 2, and is in a Factory default setting state. It will not accept Router 2's configuration information via restore. Hence this posting to find out why.

 

So today, I put both .cfg files on a thumb drive and went to one of my Linux systems (Raspberry Pi) and ran a "diff" on them. What I found was that both files are identical except for a 6 character sequence at the end of each file which was different. I then ran a "hexdump -C" with output to a file to determine what these characters were, since a couple of them were of the non-printable variety. A subsequent "diff" on those two files revealed a difference on the very last line of the file. I can't tell if it's some sort of checksum or just what. But whatever the case, whatever this "Backup Settings" function is outputting, the "Restore" seems to object to the contents.

 

If that's not weird enough, I ran 11 tests yesterday starting from factory reset to see what parameters I have changed during configuration that might cause the problem..  As far as I progressed, all went well and the backup-restore cycle worked. I'm not yet done with that testing process. I even checked file permissions on the Windows 10 system getting the files - full control on all for anybody on the laptop. So not a permissions problem as far as I can tell.

 

I even viewed the "Backup" page source code to see that programs in the router might be accessed for the function. So far no clues there either.

 

If anybody from Netgear reads this, do you have any guidance? I mean, I can go manually make all the required configuration settings by hand, and that would take a while. Why do that if you provided a function for backup and restoration -- except that it does not seem to work. And I find it difficult to believe that I have 3 defective routers, all defective in the same way. The odds would seem to be against that, I would think.

 

Thanks in advance to anyone who has an idea what to try next, or what might be wrong. I'm running low on ideas now.

 

 

 

 

 

Message 4 of 7
Sec_Engineer
Tutor

Re: DGND3700V2 refuses to restore from any saved settings files

08/25/2022 Update:

 

So this morning, I attached the master DGND3700v2 router to my linux system via Ethernet cable with no other network connections of any kind - just the Linux host and the router. Using the Chromium web browser on Linux, I connected to the router, browsed to the settings backup page and backed up the settings - twice. As the router is Linux based, I wanted to eliminate any file system issues when saving to a windows platform that might possible exist.  Next I reconnected the router which I want to clone to, reconnected and attempted a restore setting operation.  It failed - not surprised... But this time the error message was different: it said: "Restore failure! Config Check Fai!"

 

I opened the .cfg file with the nano editor, scrolled to the bottom and see that the additional past the last readable line of settings text is a collection of different characters from any of the other backups I have taken. So I deleted those and tried again and it's back to the "Restore failure!" message.

 

So Netgear folks - any thoughts as to what is going on here? Is it the backup file writer or the restore file reader that is causing the problem? Obviously they disagree on the file contents.

 

I have pretty much eliminated the external factors in the receiving environment. Surely this cannot be that hard to solve. And if you by chance reused this backup/restore code in current products, then those customers will likely have similar problems.

 

So let's see if we can find a solution. If there is any other test you'd like me to do, just let me know.  My next step is to take a network sniffer to capture the traffic both during save and restore to see if the messages are identical.

 

 

Thanks for your time and any help you can provide. Have a great day!

Message 5 of 7
w3wilkes
Prodigy

Re: DGND3700V2 refuses to restore from any saved settings files

Two things...

1-The only suggestion I have is for you to go to the firmware downloads for the DGND3700v2 and try going back to an older version of the firmware and trying the backup restore function. If it works with an older version that pretty well nails it as a Netgear firmware bug.

DGND3700v2 | Product | Support | NETGEAR

2-Netgear is not known for their support of current, let alone older EOL consumer grade devices. We almost never see anyone from Netgear on these forums. Netgear says these forums are "user to user".

 

I'm sure this is not the case as you sound like you know what you're doing. Are you sure you're working with v2's and not v1's? The v1's have no version # on the device. If they were v1's I'd highly recommend you use the 3rd party firmware from this site. Netgear could only dream of creating this quality. The firmware adds back the VDSL support that Netgear initially announced for the v1 but never provided.

Message 6 of 7
Sec_Engineer
Tutor

Re: DGND3700V2 refuses to restore from any saved settings files

Thanks for the reply. Yes, all 3 routers are of the -v2- variant and as I recall, this was a problem at least 2 versions back as well, as I have kept my routers upgraded over time.

 

I've pulled down the GPL code repository to continue my investigation. I can always build a replacement version if I need to I guess.

Your comment about Netgear support is true for not only them, but most consumer networking product manufacturers. In fact, when my power adapter died, the manual says to only use the Netgear supplied power adapter - yet they do not sell any replacements !!! 

 

Go figure that one out...!

Thanks for your time. Once I finish my code investigation and the network capture, I'll post the solution here once I have one in hand.

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