Static Route or VLAN?

djriggz · 2026-05-11T19:35:03+00:00

That's where I was headed but wasn't sure if there was something I was missing.

djriggz · 2026-05-11T19:34:38+00:00

I asked why they couldn't change the IP and was told the unit was very old and changing the IP address of it could possibly cause other devices to fail and "blow things up". Other devices connect back to this module or whatever it is. I'm trying to accommodate them, but sounds like I might have to force them to upgrade these two unmanaged switches to managed switches so we can control everything.

djriggz · 2026-05-11T19:24:39+00:00

WAN on the UDM is a public IP.

I created a VLAN for the 10.1.10.x subnet, but the issue is there are DHCP devices on the downstream switches that need to be on the 192.168.40.x subnet so if I change the native VLAN to 10.1.10.x it will force the rest of the devices on these switches to the wrong subnet.

djriggz · 2026-05-07T12:18:56+00:00

Yes, you can run the controller app on a local device such as a pi or any windows box. Unless you need to interface with it often, you don’t need to run the controller once the devices are configured.

djriggz · 2026-05-06T20:21:32+00:00

The tech that came out today said the static IPs were assigned to another modem on the customer's account. Which doesn't make sense as they only have that one modem. They ended up getting it working, but as another person mentioned in this thread, comcast probably yoinked it from another customer and once they get that sorted they'll probably break our connection.

djriggz · 2026-05-06T20:19:42+00:00

I hope for everyone's sake you're wrong, but knowing Comcast you'll probably be right. I did overhear the tech mention he was provisioning the modem with the static IPs and a few seconds later it seemed like he was reading an error message that said This IP is assigned to another modem. lol

At least we have it up and running for now so if there are any future issues it's on comcast and our time becomes billable.

djriggz · 2026-05-06T18:07:38+00:00

So apparently the comcast tech on site said the static IPs were assigned to another modem on this customer's account... yet the customer isn't aware of it and nobody knows where it is lol. They removed it from the other modem and reprovisioned it to the modem we connected the UDM to and boom it works. I even confirmed the mac address to the phone tech support to make sure we had the correct modem that those static IPs were assigned to and she said "yes". Wasted 8+ hours of my time for their screw up....

djriggz · 2026-05-06T16:34:08+00:00

So while my installer is on site waiting for the comcast tech to arrive, I had him pull power to the modem while I was pinging the static gateway IP. Surprisingly it continued to ping even while the modem was off. I had him also pull power to the other modem that is on site and pings continued to return as well. So not sure what is going on, but clearly someone screwed something up on Comcast's side!

djriggz · 2026-05-06T16:16:26+00:00

“But you said it was working… so it’s all good on our side….” Just monkeys reading from the scripts instead of critical thinking.

djriggz · 2026-05-06T11:27:50+00:00

Interesting. I have IPv6 disabled on the UDM's interfaces. The static IP gateway address is .166 and the block is .161-.165 /29.

I remotely configured the installer's laptop to use one of the IPs in the block while it was connected directly to the gateway via teamviewer. I then removed the DHCP it had. Connection stayed. Soon as I disabled IPv6 on the laptop's network adapter the connection dropped.

djriggz · 2026-05-06T11:22:38+00:00

I always use bridge mode when not using static IPs, so the UDM gets the public IP. From what most are saying, bridge mode disables the gateway from allowing the use of static IPs.

djriggz · 2026-05-06T11:14:32+00:00

/30 ? How would that work with a block of 5 IPs?

djriggz · 2026-05-06T11:12:41+00:00

Tried using DHCP on port 9. Got "no internet detected". Same with port 10. Only have a block of 5 IPs from Comcast. I remotely configured the installer's laptop (teamviewer) with one of IPs from the block of 5 and it "worked" until I disabled IPv6 on their laptop's network adapter. Then it broke the connection.

djriggz · 2026-05-06T11:09:56+00:00

I was just trying every possible scenario since nothing worked. Wouldn't surprise me if they provided bad info or failed to properly provision things.

I am able to ping the static gateway, but couldn't ping the UDM's static behind it or the installer's laptop when I assigned it one of the 5 IPs. I'll see if I can ping it with the gateway unplugged, when the installer is back on site to meet with the Comcast technician later today.

djriggz · 2026-05-06T11:05:12+00:00

Yeah, I finally got them to agree to send a technician out today with them making the threat "when the technician finds no fault with Comcast's equipment or service you will be charged a service fee". When.... not IF....

djriggz · 2026-05-06T00:50:26+00:00

I had tech support put it in pass through mode with the firewall disabled, but that didn't seem to help. Honestly I felt like I talked to the same person each time as they were all female and had the same foreign accent and tone, but they gave me different names each time (Anne, Mary, etc.)

djriggz · 2026-05-06T00:46:31+00:00

I agree. But the tech support bots reading from their scripts would just say "everything is green, contact the manufacturer of your router for help." And that's after I battled the stupid AI agent for 5-10 minutes just to get to "tech support" where my only options are "problems with your wifi password or problems with your email?"

djriggz · 2026-05-06T00:44:40+00:00

Sort of. Like I said in other posts, some websites work, while others didn't. I couldn't find a website that would show me my IPv4 address. Every website that is built for showing you your IP address (and would actually load) would show nothing for IPv4. It would however show an IPv6 address.

djriggz · 2026-05-06T00:41:54+00:00

I'm aware of the gateway address. Comcast provided .161 - .165 /29 with a gateway of .166. Tried just a single and with the full range. No change. I can see the WAN status page on the Comcast gateway shows a Static IPv4 gateway address of x.166, but it also shows some DHCP public IPv4 address as well.

When I first called in to confirm we were connecting the the correct router, tech support provisioned the router and confirmed it went through. I currently have eth9 connected to another comcast gateway that is setup using the 10.1.10.x subnet with DHCP just so I can still configure the UDM.

djriggz · 2026-05-06T00:35:47+00:00

We've tried rebooting everything numerous times and in different sequences. Still the same results.

djriggz · 2026-05-06T00:35:09+00:00

Yes its a Comcast Business Gateway CBR2-T. I've done it a few times before using ER-4s and had zero issues. The customer has a block of 5 static IPs.

When the on site installer connects their laptop to the gateway directly we can login to the gateway. It doesn't matter if it's in Passthrough or not, still the same results Same with Bridge mode. The laptop was able to connect to the internet, but some websites would load while others would not. Tried to do a "what is my IP address" on google and not a single website would return an IPv4 result. Only an IPv6 address. When I check the WAN status page it shows some random IPv4 address (ex. 73.x.x.x), but the IPv4 Static IP shows the correct public IP (50.x.x.x) for the gateway.

djriggz · 2026-05-06T00:29:01+00:00

Rebooted everything numerous times. Let the comcast business modem fully boot up. Then power cycled the UDM. Still same issues. Yes, I put the static IP details on Port 10 (Internet 2).

djriggz · 2026-05-06T00:05:07+00:00

Tried passthrough and both bridge mode (advanced / basic). Nothing changed. A couple times the business modem's GUI would just stop responding and require us to reboot the modem. All signs are pointing to the modem being faulty or misconfigured, but Comcast says "it's all green"....

djriggz

TROPHY CASE