Enabling IPv6 on untrusted Ethernet1/1 interface brings down IPv4

[bryanscott]

I tried working with Palo Alto support but there hours don't match with my schedule. 

I decided to start using IPv6 on my local LAN and WAN. 

I setup a DHCP server using MS Server and created a scope. Devices on the network are getting two IPv6 address. 

I configured the IPv6 on PA-220 and hit the enable button and committed and immediately lost the IPv4 network from Xfinity. I currently get my IPv4 via DHCP.

After about a week of this I contacted support and open up a case via the Palo Alto web portal. They couldn't answer the basic question, why enabling IPv6 would bring down IPv4. Even if I don't have anything configured it brings down the IPv4. Just enabling it brings down the interface. I know I'm getting IPv6 from Xfinity. I did a packet capture. 

During this time, I configured a Cisco RV340 and have no issues with both IPv4 and IPv6 working on the untrusted interface. I could continue to use the Cisco RV340 but it's not a NGF. 

If needed I could provide configurations, but seeing I can get it  to work on a Cisco small business router I wonder what is going on. I was on version 10.x software. I downgraded to 9.1.x just to see if it was a problem with the code. No change. 

I contacted Xfinity and they say both can work at the same time. They also provided the Prefix to use. It's in the screenshot. 

[erikda]

Can't explain why IPv4 goes down, but be aware that Palo does not support DHCPv6 prefix delegation, which is kinda mind blowing.
Been requested for a long time, but seems like IPv6 doesn't get any attention.

[Bryans1367]

I replaced the Netgear CM1100 modem with a Arris T25 modem and the modem does not reboot after I enable IPv6. 

I found a post on Netgear's support website that others are having the same problem with different firewalls.