I have this SAME EXACT PROBLEM!!!  My G34 is in warranty until September 2024.  I called tech support, and the guy told me they cannot help me with a port forwarding issue unless I purchase PREMIUM TECH SUPPORT for $39.95 for 1 day or $89.95 for 6 months.  THIS IS EXTORTION!  I expect ALL features of my G34 to work UNDER WARRANTY without having to pay more money for tech support that I don’t need.  This has nothing to do with the devices on my network.  I am not some “newbie” to this sort of thing.  have been using port forwarding on many different routers over the past 20+ years and never saw an issue like this.   Port Forwarding to these devices has worked flawlessly until November 1st.  I have done a factory reset but that hasn’t helped.  Below are screenshots of the Port Forwarding page BEFORE November 1st and AFTER November 1st.

I have entered the EXACT SAME information as the BEFORE picture, but The SERVICE NAME, SERVER IPv4 ADDRESS, and INTERNAL/EXTERNAL PORTS DON’T SHOW UP!

One thing I am wondering, is that during the setup, it wants an IPv4 adress and an IPv6 address.

Previously, you could enter the IPv4 address (or select the “connected device”) and ignore the IPv6 address, and it would “grey out” the IPv6 address before you clicked on “SAVE”.

Now, it still seems like it NEEDS the IPv6 address, even if there isn’t one.  The last four segments that used to be “greyed out” are now still boxes waiting for information.

Could that have anything to do with it?  My devices don’t even have an IPv6 address, as I have disabled that since DAY 1.  It’s never been a problem before.

IS THERE ANYONE WHO IS EXPERIENCING THIS SAME ISSUE THAT AS A SOLUTION/WORKAROUND?

Basically, as of now, I can’t use my webserver or my camera, since I can no longer forward the ports for external access.

I CAN access these devices by there LAN IP as long as I am at home on the same network, but I can no longer access them from the outside world as I could before whatever happened on November 1st.

If Arris won’t honor their warranty on this unit (without my having to spend EXTRA money for their “Premium” tech support) by either fixing this issue, replacing the unit with a new one, or refunding my money, then I will NEVER purchase another Arris device again, and I will make sure that I tell all my IT/tech friends to not purchase Arris products as well.

This is completely ridiculous!!!

Just as an aside, I also DID reboot/power cycle the devices that are attached with no change.

I did just check the software page on the unit and noticed it is different than it was previously.

Could it be that a firmware update was pushed through that is screwing things up?

Will there be a fix/patch/update for this SOON?

Is there a way to go back to the previous version?

My port forwarding also stopped working around 11/01/23, so maybe it is related to the same firmware “upgrade” from Comcast/Xfinity!? You replied on my forum thread as well. That firmware version does look familiar. Sadly, I cannot access the WebAdmin GUI anymore, it just spins and spins and eventually gives me an invalid operation pop up now. That might be resolved with a reboot, but I’m afraid to do that right now because I have it partially working and don’t want to mess with it.

I have a replacement unit coming to me, but if this is a problem with that firmware version then the same problem will happen again. Port forwarding is a feature of the router, and was working up until 11/01/2023. If it is a problem with the firmware then Arris must resolve this with Comcast/Xfinity!

I have the answer now.

Apparently the issue with this firmware update is that your DHCP pool needs to be from X.X.X.2 - X.X.X.253.

Previously, I had my DHCP pol from X.X.X.110 - X.X.X.150, leaving my “reserved/static” devices below 110.

That no longer works.

Here’s the steps I took:

1. Login to gateway web GUI
2. Factory reset (clicking the RESET GATEWAY button in the Troubleshooting section)
3. After the RESET, login to the unit
4. Check the DHCP Pool 
5. Go to the Connected Devices page, and reserve any static addresses by clicking on the “+” to the right of the device
6. Setup your Port Forwarding rules.
7. Now the rules will save.

The whole issue was that the DHCP pool needs to include ALL addresses now.

I verified this after getting everything working by changing the DHCP pool back to what I previously had (X.X.X.110 - X.X.X.150) and Port Forwarding no longer saved the results.  I then changed the DHCP pool again to X.X.X.2 - X.X.X.253 and BAM!  port forwarding works again.  (I did have to re-enter all my rules again because of the changing)

(Side Note: Doing a factory reset will NOT go back to the previous firmware version, as that is apparently pushed through by the ISP)

Hope this helps others who may be pulling their hair out over this update.

The bug is apparently triggered by modifying the DHCP address range. See this forum topic for more details.

The DHCP Pool must be set to the default of 2 to 253. If you change this then Port Forwarding will stop working. More details can be found at this forum post.

Gateway > Connection > Local IP Network > IPv4 > DHCP Beginning Address: 192.168.0.2
Gateway > Connection > Local IP Network > IPv4 > DHCP Ending Address: 192.168.0.253