Yeah, that's exactly what I have seen in the past. No esp packets coming back, they're dropped incoming when in bridge mode. I have had better luck with a replacement modem sometimes. --Brendan On Mon, May 12, 2025, 17:41 Christopher Aloi via NANOG < nanog@lists.nanog.org> wrote:
Thanks Eric and Brendan. Yes, this is specifically related to when we put the rac2v1s in bridge mode and I bind one of the static public IP addresses to my router. If I captured packets on my router I can see GRE packets leaving my router destined for my data center, but I never see any of the return packets I send. They are being lost/dropped on the way back in. I am up to 30 of these now. What I can't grock is why they come in at a rate of ~5 every morning. If anyone has any contacts at Spectrum that might listen, or a workaround, please let me know!
On Mon, May 12, 2025 at 4:04 PM Eric C. Miller via NANOG < nanog@lists.nanog.org> wrote:
Sorry, no help from here per se, but I used to get into the same situation with AT&T Uverse routers. It seemed to be an issue with the built-in stateful firewall of the DSL router. I was able to get around it by having tunnels to multiple public IPs and rotating their usage with a script on our equipment. The problem seems to self-resolve after a reboot. Very frustrating when you pay for static IPs.
Good luck!
Eric ________________________________ From: Brendan Carlson via NANOG <nanog@lists.nanog.org> Sent: Monday, May 12, 2025 3:20 PM To: North American Network Operators Group <nanog@lists.nanog.org> Cc: Brendan Carlson <brendan@bcarlsonmedia.com> Subject: Re: Spectrum & GRE
I've seen the same thing on those same models with them being in bridge mode specifically. They generally have issues with gre and l2tp tunnels.
On Mon, May 12, 2025 at 12:13 PM Christopher Aloi via NANOG < nanog@lists.nanog.org> wrote:
Hey All,
Hoping someone can lend a hand here. I have ~ 1k customers running GRE tunnels back to me for VoIP. Over the last three weeks these tunnels have started to break at a rate of 3-5 per day. We've narrowed it down to customers using specific Spectrum routers (rac2v1s and rac2v2s). I am still able to access the public IP but the tunnel drops and will not come back up. The fix has been to reconfigure as VPN or have the CPE router replaced with a rac2v1k. I have been unable to get anyone to listen to me at Spectrum as these accounts are owned by the customer and I can't prove a systemic issue. I have a list of accounts that have been impacted. Has anyone else encountered this? Any contacts at Spectrum that might listen to me? I am fearing all of these tunnels will go down at some point.
Thanks,
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