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20 Messages

Tuesday, September 1st, 2015 2:00 PM

IPv6 stops working after a week

After about a week (I'll try to get a better measure of time next time) the Comcast modem refuses to respond to IPv6 packets. A power-cycle always fixes the problem, but unfortunately, it sometimes gives me different addresses.

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575 Messages

9 years ago

Hello StarNet,

 

Are you still having issues with your IPv6 connection?

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20 Messages

9 years ago

Yes, someone here just noticed that it wasn't working today. (We don't often notice quickly, because IPv4 continues to work. What brought it up was that we have a Debian system directly on our Comcast network, and the admin was using apt-get, which connects to many sites at the IPv6 addresses. This would time out before going to the IPv4 address.) Power-cycling the Comcast modem solved the problem, as it always does, but I know that after a week or two, it will fail again.

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575 Messages

9 years ago

Would you send me a private message with your account info including yout modem model so that I may investigate this issue?

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20 Messages

8 years ago

In response to your last private message, I called the support number yesterday and spoke with someone who moved the ticket to tier 2. When they didn't contact me in 24 hours as promised, I called them today and didn't get very far. After a long conversation that didn't get anywhere, the (tier 1) tech I talked to told me that the Comcast modem couldn't route both IPv4 and IPv6 at the same time.

 

One interesting piece of information in yesterday's call was that the tech couldn't connect to my modem, even though it's routing IPv4 just fine. Perhaps the same failure that is causing IPv6 to stop working is also causing the remote management to stop working?

 

I'm not sure where to go with this. If I don't hear anything more in the next day, I'm just going to reset the modem again and keep doing that until the static addresses get rolled out.

 

By the way, for the benefit of those who didn't get my private message to Michael, the modem in question is a SMC, serial number H2120223DB75, firmware 3.1.6.56.

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20 Messages

8 years ago

Now IPv4 isn't working either... I will power cycle the modem.

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326 Messages

8 years ago

this is a known problem (well, known to me and some other posters) with IPv6 and the SMC.  You can fix it with a $10 lamp timer from the hardware store.  Plug the modem into the lamp timer and have it power-cycle the modem at 3am every night.

 

Or you can have comcast replace the modem with a netgear if you don't like rubber band solutions.

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610 Messages

8 years ago


@tmittelstaedt wrote:

this is a known problem (well, known to me and some other posters) with IPv6 and the SMC.  You can fix it with a $10 lamp timer from the hardware store.  Plug the modem into the lamp timer and have it power-cycle the modem at 3am every night.


Jeez what an ugly hack Smiley Wink

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326 Messages

8 years ago

I used that hack on a specialized credit card processing system that used an MS-DOS gateway and the device ran flawlessly for over a decade.  The bank got pissed at me because we never upgraded.