Forum Discussion
Nighthawk M2 IP PassThrough stops working when idle
I'm seeing something similar with the M7 Pro. What I've found through looking through packet captures is that the M7 stops responding to ARP requests even though it's still sending them out. The ARP cache expires for the ARP lease on the M7's gateway IPv4 address and now packets can't be sent to previous IP address because the ARP table entry has expired.
Due to the IP PassThrough work you don't really connect to the CGNAT gateway directly to its MAC its more like NAT 1:1. I've not had any more problem since so something the ISP was doing. I would think the M7 is the same with a 2 minute lease? But what the M7 has WAN side of the NAT 1:1 is anyone’s guess.
you don't really connect to the CGNAT gateway directly to its MAC its more like NAT 1:1.I have many questions...
On what is this statement based? How is CGNAT relevant here?
People can often have different meanings when they refer to "NAT 1:1". Is there a specific RFC that refers to the specific type of NAT 1:1 to which you're referring?
Regardless of the type of NAT, if an IPv4 node is supposed to send packets to another IPv4 node, how can it do so if it does not know the layer 2 MAC address to which to send those packets? i.e. how is any IPv4 node in a segment supposed to send its packets to its IPv4 gateway if that node does not have the MAC address? Shouldn't the bridge still respond to ARP requests? If not, why? How can it act as a layer 3 gateway if there is no layer 2 address? Broadcast?
Well mostly all mobile broadband operators and in here the UK you will never get a WAN IP to your device so CGNAT gives out 10. IPs some times 100. IP's which is still not a true WAN IP and SNAT out a real WAN IP.
What IP PassThrough does is take the IP it gets on its WAN side then gives it out on the LAN side be it a WAN IP or 10. IP but it is not a transparent bridge if it was the source MAC ARP from the gateway would not be Netgear MAC which it is. So the IP PassThrough on its WAN side does DHCP for a IP does ARP to the real gateway then your connected devices does DHCP to the Netgear gets the same IP Netgear does ARP to Netgear gateway LAN side and traffic is passed over.