1g Cable Modem

[Tabita Knezevic]

Ipurchased the AC1900 C7000v2 cable modem for use with Spectrum Internet a few years back. Everything has worked fine until a few days ago. My instincts told me to update the firmware (currently V1.02.09).

As the Netgear Genie (internet portal) listed nowhere to update the firmware, my investigation lead me to download and install the iOS app and waste time setting up an account. After installing the iOS app I was excited to see the app confirm that the firmware was out of date... but gives absolutely no way to download and push it to the modem. I was frustrated and annoyed to discover that other uses have had the exact same experience with Netgear offering no specific solutions - especially for this model.

Right now it's all working and the page you suggested I look at shows that the firmware listed above is the only firmware approved by Spectrum even though 2 newer versions are available. As mentioned I haven't had a problem today (and I think that the real issue was on Spectrum's end).

I'm looking for a cable modem router that has VPN capabilites as an all in one package. Ive been looking through forums and articles and nothing seems to match what I'm looking for. Are these even a thing? If so, what models are affordable. I'm looking to spend around $300 max. Thanks for the suggestions/information

I recently got an EX2300 for use in a small office. I've configured the switch to hand out DHCP addresses to clients on a vlan. The ge-0/0/0 interface is configured to get a DHCP address from the modem. The modem itself is in NAT with Routing mode, but any client connected to the switch is unable to get out to the internet.

From the switch's perspective it can ping the internal l3 interfaces, it can ping the modem, and it can ping an external web address. The l3 interface is able to ping the switch, but cannot ping the modem/gateway. The best I can come up with is there is a route missing from the modem back to the switch, but the modem doesn't allow me to configure any static routes. The static route in the switch is automatically created when ge-0/0/0 is connected and is the local IP of the modem.

Are you able to ping the switch from the modem? The only IP address on the switch I could find from your config is the IRB 62. What is the interface that goes to the DHCP Server or Modem? There is no static route or any routing configured on the switch.

Also, do the clients get an IP address via DHCP through the switch? You mention that a static route is automatically created when ge-0/0/0 is connected but can you try to configure it before connecting ge-0/0/0?

The interface connecting the switch to the modem is ge-0/0/0 it is set to family inet dhcp and gets an IP address from the modem (192.168.0.2 to be precise, the modem is 192.168.0.1). No there is no static route configured because the 0.0.0.0/0 next-hop is created automatically when I connect the switch to the modem. I have also configured this manually, but it has made no difference in irb.62 being able to ping the modem.

Yes the clients get an IP address from the switch when connected. All of that works as expected. They recieve a 192.168.62.x address within the defined boundry and can ping each other with no issue, they just don't appear to be able to get beyond 192.168.62.1 (the address is both the router defined in the DHCP settings and the IP of irb.62 which handles the routing for that vlan).

If source IP 192.168.0.1 can access the internet but not others in vlan62, then we are probably looking at a source-nat requirement that usually is supported on SRX or MX devices. You can check with the vendor but I don't think such basic modems have the capability of configuring a return route for your internal networks.

Or just use another VLAN that can get internet access. However know that if we create a separate VLAN for this purpose, then only that VLAN will have internet access (anything sourced from vlan62 won't).

Thank you for your advice. It appears configuring it so that the vlan, irb, and the port connected to the modem are all on the same network as the modem itslef then everything works. Clients get out to the internet without issue. I am going to outline the configuration below, but then I have a couple of questions. Networking is by far my forte, but I want to understand why this does/does not work a little bit better. I will say that I based a lot of my configuration of this small office on our home office which is running EX3400s and an SRX. All of the routing happens on the SRX and of course there is NATing occuring on the SRX. Perhaps my expectations were that the Modem would be able to handle the same job the SRX is doing as far as the NAT is concerned, but anyway, I will ask my questions below.

I tested the configuration without the static route as well and it works. I'm assuming there are no static routes needed because the client/vlan/and modem are all on the same network and thus don't need to route across networks. Is this accurate?

Since we are not routing within the switch given the above configuration is the irb even needed? Again since everything is on the same network we're practically in "dumb switch" mode are we not? I am going to test this later today for my own curiostiy.

So, I guess my question is, why is the vlan configuration not working as I expected it to? Is it a route back to the vlan that is missing because the modem doesn't know what to do with the traffic? On my main network I have 8-9 vlans with a single static route of 0/0 out to the ISPs gateway. All of the routing is happening on the SRX though, the switches just do ethernet-switching. Is this not similar to the configuration I initally had? Is there some "magic" (high tech term there) that the SRX does that it doesn't need additional configuration to route traffic back to the sending client? If I was able to define a route back to the switch from the modem (I'm assuming this would be something like 0.0.0.0/0 next-hop 192.168.0.2 for a return path from the modem to the switch if I was actually able to configure it) would that do what I was originally trying to accomplish?

As of right now, to your point mriyaz I don't think I can do multiple vlans on this switch with this modem that would allow all clients regardless of their vlan to get internet access. I may play around with my limited understanding of trunks to see if I can get something going, but since the only way to get things working so far has been to put the vlan on the same network as the modem I don't think trunking will accomplish anything.

[ANS] No, that must be because the clients are already ARPing for the gateway and the EX is just doing plain switching and not routing in this case. So it looks at the destination MAC and forwards packets out of ge-0/0/0. That's how it must be working without the static route.

[ANS] You'll need the IRB if you have any other VLAN and need to allow IP communication between VLANs. Note this is independent of the fact that your other VLAN cannot get internet connectivity in this set up.

[ANS] If possible, on your working setup, just check if the SRX has a return route for the other internal VLANs/networks that it provides internet connectivity. I think that's the only difference here, the modem isn't smart enough to do routing back to the internal networks like an SRX.

On my main network I have 8-9 vlans with a single static route of 0/0 out to the ISPs gateway. All of the routing is happening on the SRX though, the switches just do ethernet-switching. Is this not similar to the configuration I initally had? Is there some "magic" (high tech term there) that the SRX does that it doesn't need additional configuration to route traffic back to the sending client? If I was able to define a route back to the switch from the modem (I'm assuming this would be something like 0.0.0.0/0 next-hop 192.168.0.2 for a return path from the modem to the switch if I was actually able to configure it) would that do what I was originally trying to accomplish?

[ANS] Not really, you need a route like 192.168.162.0/24 with next-hop as 192.168.0.2 (assuming internal network is 192.168.162.0/24 and 192.168.0.2 is the switch interface connecting to modem like before). It's unlikely the modem will have this capability. The reason why you're idea of 0.0.0.0/0 next-hop 192.168.0.2 is incorrect is that doesn't make sense of how the modem will not hit that route for internet traffic? Hope you get what I mean here.

While it isn't my preferred route, for now a single vlan will have to do, I'm just a little mad at myself because I could have accomplished the same thing with a much cheaper piece of hardware. Once I have time and the funds I will look into getting an SRX setup in this office so that I can actually take advantage of the hardware.

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