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dfp21's profile

New Member

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8 Messages

Thursday, August 4th, 2022 8:22 PM

Closed

ipv6 does not work

router can't ping any IPv6 destination: PING www.bing.com (2620:1ec:c11::200) from 2600:1700:878d:4010::1: 56 data bytes --- www.bing.com ping statistics --- 4 packets transmitted, 0 packets received, 100% packet loss

New Member

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8 Messages

2 years ago

I have not changed the MTU

Community Support

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232.2K Messages

2 years ago

Here to help with your router, @dfp21

 

Have you performed your factory reset yet to help with your dropped packets? Answering this should help us pinpoint the next steps to take.

 

Please reach back out if you need any additional assistance.

 

Latoya, AT&T Community Specialist

 

 

 

ACE - Expert

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35.6K Messages

2 years ago

The MTU default is 1472, not 1500.  If you didn't change it, who did?

New Member

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8 Messages

2 years ago

The factory-reset worked. IPv6 magically worked immediately after the router booted up. Thanks for the suggestion.

The router can now ping IPv6 destinations, and all my endpoints connected to my TP-Link APs now get 10/10 at test-ipv6.com. The AT&T router is configured with "IP passthrough" enabled and the TP-Link router is configured with IPv6 "bridged" mode.

Also, for the person talking about MTU, the default MTU on this router is 1500 apparently, since that what it is right now immediately after the factory-reset. 1500 is a normal MTU value, by the way.

ACE - Expert

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35.6K Messages

2 years ago

The MTU has to be smaller than the default Ethernet MTU of 1500 if using 6RD (i.e. tunneling).  AT&T should be pretty much native IPv6 now, so 1500 should be okay now.  I pointed it out because if your MTU is too big, since IPv6 doesn't fragment, it will not work which is what you were seeing.  I also now see that you cannot change it.  I have it disabled, so it doesn't really matter, but mine shows 1472.  

Community Support

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232.2K Messages

2 years ago

We're glad to hear that the factory reset got your IPv6 working, @dfp21!

 

Should you ever need any further assistance from us going forward, please don't hesitate to reach back out, and we'll be more than happy to help.

 

Thanks for being the best part of AT&T!

 

Jarod, AT&T Community Specialist

1 Message

3 months ago

I have had AT&T Fiber since September 2023 and IPv6 does not work properly. It appears AT&T has not configured it correctly. I reported this back in November and it still hans't been fixed. I simply turn off IPv6 on the AT&T Fiber Gateway then all network traffic works as it should.

ACE - Professor

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5.6K Messages

3 months ago

Nope.  Open a new thread and be prepared with facts.  

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