Dahua NVR - "It has reached the connection threshold!"

Sep 10, 2019
23
6
US
Started getting this last night.

At first, I was having issues saving configurations from the cameras.

I know the device has a"'connection limit" of 128, but I don't know what it considers a connection.

Clearly not a user session - as there are only two actual users, and we both use the admin account.

The other user only uses his iphone, and I know definitively how many sessions I have open at any given time.

In any event, I changed the max connections on the NVR to 0 - which is supposed to mean no limit.

It cannot mean a literal zero, as that would mean setting it to zero would require factory reset to recover, as even local login is a network connection via the loopback.

So, I then logged out and tried logging back in, and got the "it has reached the connection threshold" message.

I went into the firewall and set connections to be allowed only to my remote subnet, then killed all connection states.

I don't know what the timeouts are on the NVR, so it could be strangling itself by spinning off connection attempts faster than they time out, though it shouldn't be, as I am refusing packets rather than silently dropping them.

I had someone on site power cycle it - no change.

Have to schlep over there and try a local login.

With dahua cams and nvr, and gdmss, do I need to run the onvif service?
Or is it only required for third party camera compatibility?

It's still operational, as I am still getting Tripwire emails, so it's making outbound connections.
(I disabled the firewall restrictions after it was power cycled.)
 
Just in case anyone else runs into this....

The docs that indicate setting Max Connections to zero for unlimited is incorrect.

Setting it to zero completely disables remote access.
It does not disable local login via loopback.
 
This happend to a lot of folks a few updates ago of the beta software they call iDMSS. The app makes a bazzillion connections for some reason I thought the newer (but still broken) iDMSS versions fixed it? You may also verify the NVR is set to 128 connections, it is editable.
 
This happend to a lot of folks a few updates ago of the beta software they call iDMSS. The app makes a bazzillion connections for some reason I thought the newer (but still broken) iDMSS versions fixed it? You may also verify the NVR is set to 128 connections, it is editable.

I suspected it was something along those lines.

In my implementation, there are two owners using the mobile app exclusively, a TV used as a local monitor via chromecast and me occasionally monitoring the system.

Both owners are functionally illiterate, so when I set up their mobile app, I just used the default admin account, which is also what the chromecast connection uses.

Since I changed my connection to use a different account, I have not had the problem recur.

I was also using both a web connection and SmartPSS at the same time remotely, and in SmartPSS I had the cams set up discretely as well as via the NVR.

There being a design flaw in iDMSS makes sense, as the way I've seen the multiple connections across my firewall, that 128 would be chomped in a heartbeat.

That actually calls into question what the 128 actually limits.

Is it connections, or users, or some derived metric?

If it's connections, does it include half opens, and what is the timeout?

Not asking for answers here - just observing that there are a lot of unknowns, so I can see that connection count getting maxed pretty easily depending on state timeouts from the perspective of the NVR vs the router, and what states each considers to exist.

As I ruminate on this, I'm wondering if I just had a lot of half opens from tweaking and tuning settings directly on each camera.

If I was closing browser tabs rather than logging out of the camera each time, those half opens could have stacked up depending on timeouts.

Just did a quick check - from idle state with 8 connections, opening gDMSS Plus brought the connection count to 32.

That's with just 5 cams.

Opening SMartPSS opens 11 connections, but they drop off after about 30 seconds.

Opening cams in live view does not open additional connections to the dvr, which is as expected, since the connections are actually to the amazon server.