Re: Spectrum & GRE

[Christopher Aloi via NANOG <nanog () lists nanog org>]

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,
> >
> > Chris
> > _______________________________________________
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> >
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