ipv6 broken?

after a quick google search it seems to a problem with packets and the MTU :

http://www.dslreports.com/faq/uverse/4._Setup_Operation#17822

Technically what's going on is the packets are too big for the alloted MTU to handle

a Quick run down of these two Technological Terms is that a "packet" is a digital piece of information that allows things like your google search query to actually reach google , think of it like words on a paper, after your finished writing , it ... you enclose in a letter and address it to google.

Google on the other end gets the letters and interprets your query, sending the whole process back to you, but with the results you wanted from your query.

An "MTU" is short for maximum transmission unit or the highest limit (size) of transmission that is allowed per packet.

basically if the packet is too big of a size, it is usually dropped, depending on what the MTU is set on.

Hope this clears up things a bit

Everything on AT&T's sites say IPv6 is supported, but I get the same issues if I try to use it.  If I disable the IPv6 stack and it uses Teredo it works, but if I have IPv6 protocol enabled it times out and many websites hang for a long time on first visit (guessing DNS craps out and fails over to IPv4?) unless I disable IPv6.  Anyone get it working?  Not a huge deal, yet, but for Xbox and some other sites it could become a problem.

I just spoke with support and didn't get far.  They said I have to open ports (and pay someone $50 to do it for me...?!?!), which makes no sense because IPv6 shouldn't need forwarded ports because there's no NAT going on.  Anyway, AT&T's own tests show my gateway/router is fine as is my PC etc. and I'm getting allocated an IPv6 IP and while it tests to the external test sites like http://test-ipv6.com/ fine using teredo it times out using IPv6.  AT&T's site says IPv6 is supported, that doesn't mean teredo (which exists for ISPs that do NOT support IPv6!) so what's going on?

3 modems, 3 weeks of calls, and a technician and my IPv6 still isnt working. ATT support continues to deny its their fault. I have 4 computers and every one of them says "IPv6 Connectivity: No Internet access" My Android phone also won't access IPv6 only sites, and several apps wont load pictures. The modem says IPv6 is enabled. http://test-ipv6.com/ says IPv6 isn't working. ATT's own IPv6 test site (https://www.att.com/support/internet/ipv6.html) won't connect to modem.

The sad thing is that I live in an apartment complex and i can walk out on my balcony and connect to the clubhouse wifi (also ATT) and it works. http://test-ipv6.com/ also says IPv6 works.

I am aware I can disable IPv6 in the modem and it will work with IPv4 as most sites (but not all) are "dual stack" so will work on either, but why should I? Isn't it reasonable to expect IPv6 to work? It's 2017. Premium Support called me back today to tell me their most knowledgeable tech told them that if it's not working, it's an issue with the website I am trying to reach. Really? My time is to valuable to continue proving they are wrong. 

I'm with you. I have the same problem and no way to fix it due to IT BEING ON THEIR END and them apparently not caring much.

It is intermittent here, like if I go to cnn.com it will load one time and if I refresh it, it will not load or half the page will load. When it is not loading none of the other pages are loading. Ipv4 works with no issue. Used to work until the last update to the gateway.