AP mode + USB modem question

[apokrif]

Guys,
Could somebody clarify how AP mode works with USB modem, please?

Setup variants:
1. Standard setup (no USB modem!) – WAN port connected to another router – everything work as expected.

2. Wireless router mode (Default): Dual WAN / Single WAN with USB modem
MiFi 6620L is in USB tethering mode, router got 192.168.1.3 IP (192.168.1.1 is USB modem)
LAN is 192.168.2.0/24
Everything works, but we got double NAT - not good...
* Looks like there is no way to switch MiFi 6620L itself to bridge mode, it always does NAT.

3. AP mode with USB modem:
(I assume USB modem will handle DHCP for the bridged network)
After reboot router has 192.168.1.1 IP, not USB modem (confirmed via arp /a)

When browsed to http://192.168.1.1 got message "Router IP has been changed, etc. "
But it doesn’t - ASUS has 192.168.1.1 still, it didn’t get IP via DHCP from USB modem (as it did in Dual WAN / Single WAN mode)...

Question:
When router is in AP mode, is USB modem "connected" to same bridge where WAN/LAN/WiFi networks are?

Could it be that ASUS got an IP from USB modem, but USB modem is not actually bridged the rest of router networks?

If there any way to find out/troubleshoot, what’s going on under the router hood in this case?

 

[RMerlin]

USB modems are not supported in AP mode. You need Router mode for these, as you need to NAT and route traffic.

 

[apokrif]

RMerlin,
Thanks for prompt response!

>USB modems are not supported in AP mode.
Yep, I got this part, see below, please.
I won’t even ask this question, if my USB modems supports passthrough / bridge mode itself.

>You need Router mode for these, as you need to NAT and route traffic.
Mine does NAT already.
Just want to see, if it can be done manually (for the sake of experiment itself)


I’ve assigned IP to router in AP mode and compared interface list
In "Wireless router mode" USB modem shoes up as
eth3 Link encap:Ethernet HWaddr 00:15:FF:22:11:10
inet addr:192.168.1.2 Bcast:192.168.1.255 Mask:255.255.255.0

In AP mode there in no such interface, so it’s not part of the bridge either, obviously.

Bridge interface list is same exactly in both modes:
vlan1, eth1, eth2

Are there any cli commands to get USB modem up manually (i.e. have it show up as interface)

Just want to see if it’s doable at all.
Web interface does show USB modem connected in AP mode, but no any IP info of course.

 

[Lt. Col. Obvious]

I'm having the same issue here. The phone is actually generating the network and can handle the routing, so the router as a router is double nat, and in AP mode it won't accept the connection. Currently testing tethering into a PC and bridging out into the router as AP.

*Edit* Working.

Phone/Tablet ---usb tether--> PC ----bridge usb to ethernet (full auto) ----> AC66u B1 in AP mode

When I first moved to test I had been trying in router mode to route any of my wifi devices thinking it was needed.... but I don't even know what the settings are. When I switched to AP move every device that had the existing wifi info saved connected as soon as it came back up without me having a chance to look and see what IP configuration the router even went into.

After the initial PC that bridges into the router the router is feeding 2 PCs, 2 TVs, 3 phones, Nvidia Shield a Chromecast and a Google Home. Everything's on the same subnet, nothing's having issues reaching the outside or being reached from it.

As a test I set my Note to only use Wifi, connected in to the now AP and turned on Virtual Desktop, and the PC and Note are both seen fine from the outside and communicate with each other fine as well. Best I've gotten out of that by far. 4k/60 for the first time. Also switched wifi off and used only mobile to force the PC screen to run outside the network and that had no issues either.

This is the first time I've gotten it all to work... and it's just an auto bridge and an AP. The phone doesn't need a router at all. It was just waiting for me to submit the rest of my independance and data. Huh... I wonder what would happen if I tethered them all at once using a USB 3 hub.

 

[Lt. Col. Obvious]

So, checking the router there's a network device that didn't exist before, and all of the names used by default in the router are different. I didn't notice that before setting as AP, but it was a while ago so I may be wrong. I now have "Arcadyan Corporation", "Winstron Neweb Corporation", and "Azurewave Technologies" and I'm pretty sure it's working in full auto because it's routing everything purely through IPV6. Everything has the same IPV6 address except the trailing %##, like the trailing bit is being used to identify individual points that are all part of the same address? I'm not a networking guy, and I've never heard if IPV6 working that way, but that's what it looks like comparing the addresses. That would make sense for being reachable from the outside on every individual device and also make sense with not being able to get it working. The focus is always almost entirely IPV4 with IPV6 brushed aside as some thing we'll use later.

 

[Lt. Col. Obvious]

Maybe Windows PRNP, not the phone. I didn't even know that was a thing and apparently that's an old thing.

Of course after having it all work for about 12 hours I had to poke at it and knock it over. I've gotten it going in that one direction enough times to know it waswas a fluke where the addresses assigned by the router before switching to ap nice just carried on... But I've tested replacing the computer hardwired to the phone into initially with two other computers everything else in places it was I can't repeat it that way.

The main office computer does does have an old Intel load balancing/teaming nic... this is a fun game.

 

[Lt. Col. Obvious]

I haven't had a lot of time to mess with this, but I'm fairly certain that despite the above it's nothing to do with Windows or the network card. Currently I have tcp/ip fully unbound from the Windows bridge and the only change is that that PC no longer shows up as being wired to the router, but the tablet does.

Is that off? So much of this seems odd and backwards. The tablet is tethered to the PC via USB, bridged to the Ethernet, but with all TCP bindings removed the PC shouldn't really be having much interaction with the line at all, right? It loses connectivity from the signal when unbound, which makes sense because it should be turning the PC into a pass through, as if there was one long ethernet cable from the phone to the router. If both lines were ethernet I probably wouldn't wonder, but with the line in through a USB tether it seems like Windows has to be interacting a bit more than that, I'm just not sure how much more. It's definitely not providing IPs and using the Windows IPV6 peer to peer networking, though, that seems pretty clear, and that's not something the network card would be doing entirely on it's own.

The Router's still using the IPv4 address I assigned it when I was trying to set it up manually, it hasn't changed from that whether the connection is live or not, but it's in AP mode and set to receive everything automatically now. From everything I'm used to it should be set up as a static network and I should need to manually give everything it's spot in that... but I don't. Whether TCP/IP is bound or unbound on the PC the connection runs through with each device all I need to do is tell it the network ssid and password and it pops right on. When I check through the Router everything's being managed in the same IPv4 Subnet.

IPv6 is the very weird one. The first three blocks on everything match, but after that they don't, excepting the link local address. And every device has one IPv6 /64 and another with those first 3 blocks matching that's /128. That sort of explains why there's 19 devices happily running off this one cellular line, and it fits with the little I know about how IPv6 should work... but it's completely contrary to how the phone carriers have things set to work or want them to. I need to find time to read a lot more on IPv6, but from everything I can see it looks like I could connect a practically infinite number of devices to this with no dhcp or management on my end at all. The phone/tablet may be doing it, but the last I knew Android shouldn't be doing so much with no input. Unfortunately none of the devices I picked up are rootable and in order to keep people from doing things like this most of the net related information doesn't even show up in a dumpsys. I've added every device I have and picked a few up but I'm not going to be able to test maxing out the IPv4 subnet much less the IPv6 that everything shows it's been assigned. I'm not sure if the US could do the second one.