Multiple routers with UPNP in a LAN

[aster1x]

What happens when there are multiple routers with UPNP in a LAN?
1. Each router opens UPNP (or even creates port forwards) only for the devices connected to this router OR do we have to port forward the same port at each router?
2. Can we have the UPNP function enabled at all routers, OR we must have only one UPNP in one router (like the DHCP Server?). In the latter case, does it matter at which router we must have the UPNP on?

 

[Carcus]

Why are there multiple routers? Explain more about the topology?

UPNP should really be disabled its a security risk and can open unnecessary ports. Specially if you have the cameras directly on the network.

Also if you wanted to be safe you should probably use a vpn. (So i dont get shunned by the admins)

As for your actual question im not sure how or if upnp advertises to multiple routers. (Never done it because upnp is crap)


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[VorlonFrog]

Are they routers or wireless access points? Any bridged network segments?
I (and a lot more people here) agree with Carcus. UPNP == BAD!! Disable it.

 

[aster1x]

One device is a modem/router/AP which is the main router/gateway of the LAN. The second router/modem/AP/VOIP ATA converter (old Fritzbox) is in bridge mode in the LAN.
Both had the UPNP feature enabled. The HIK NVR had the UPNP enabled in manual mode. When I was trying to set the 8000 post of the NVR at a different value, it would not save the value, reverting always to 8000. When I disabled the UPNP at the second (Fritz) router, the NVR successfully kept the new port value. Hence my question "what happens when we have two devices in a LAN with UPNP enabled"?. How should we manage the UPNP in this case?

Otherwise I agree with the opinion that UPNP is bad, but unfortunately I have a couple of devices that do not allow me to specify a WAN port, and they rely on UPNP to set it, hence I need the UPNP functionality