6in4 through Comcast supplied Technicolor CGA4131COM

[jimb]

Hi,

I've been a HE tunnelbroker user for 11 years using a Linux router behind my cable modem.  I have internet through Comcast and up until today had a SMC D3G-CCR set up in what they call "pass through" mode, with a /29 of IPv4 assigned.  The Linux router does 6in4 for me to the TB and provides my IPv6 uplink. 

Yesterday, this device started randomly rebooting, and they replaced it with a Technicolor CGA4131COM.

My static IPv4s and NATs and stuff are working, and connectivity directly to my outside Linux router interface works too.  But 6in4 appears to have stopped working!

From doing tcpdumps, it appears that the CGA4131COM is blocking 6in4 packets, either outbound, or inbound, or both.

Has anyone had this issue?  Is it something I can get Comcast to fix, or am I boned?

The modem does seem to support native IPv6 w/ DHCPv6 with PD of a /56.  But all I've seen about using this so far are nightmare stories about how the CGA4131COM doesn't properly route the IPv6 subnets it assigns via PD through your customer router.

So for now, I'd like to stick w/ the tunnel.  If there's no way to get them to un-block 6in4, is it possible to say tunnel 6in4 inside UDP or something like that to pass through the comcast network?  Does HE.net support anything other than 6in4?

[jimb]

Turns out that the cable modem was blocking 6in4 despite all firewalling being turned off.

I got a different model CM (Netgear CG3000CR) and 6in4 started working again.