[FS#1002] Dns ipv6 problem when interface restart

[LEDE Bugs]

The following task has a new comment added:

FS#1002 - Dns ipv6 problem when interface restart
User who did this - Mathias Kresin (mkresin)

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> Dual-stack doesn't work well with iphone and android... They get ipv6 but no ipv4... 

Well, at least the iPhone should get both. Works fine here with the config I posted above.

But to be honest, I'm still not sure if I really get what your issue is. Now the clients don't get an IPv4 address. The original issue was something about interface restart and no IPv6 DNS server (btw. there is no restart button for the interfaces, only connect and start/stop).

As Hans already said, use exactly the config I posted above for any further tests. Either drop the "option ip6assign '64'" from the guest network or better add "option ip6weight '10'" for the lan network and "option ip6weight '0'" for the guest network.

> About restart... I mean click restart in luci page. 

I'm not aware of a restart link in LuCI. You have a reboot link to restart the router. Be as specific as possible to allow us to understand which steps are required to trigger the issue. In your case I suspect you clicked either on connect or start/stop for the wan6 interface (why is it even necessary?)

Better use the command line and give us the commands you run. ifdown wan6/ifup wan6 is your friend as already said.

I still don't know to which network your smartphones connect to (lan, guest?). It is an essential information given the fact that you have multiple network.

At the moment it looks like some kind of misconfiguration to me. To rule out some possible issues please do the following:

  - use my config
  - reboot the router
  - wait for your ppp connection to come up
  - make sure ubus list network.interface.* shows only guest, lan, modem, wan and wan6
  - use "ifstatus wan6" to check if you have an ipv6-address, ipv6-prefix (with assigned to lan entry) & ipv6 dns-server
  - check with "ifstatus wan6" if the prefix gets lost after 360s or if the valid counter jump back to 360s (report if the validity of the prefix > 360s as it should be according to your package dump)
  - if everything is fine use ifdown wan6/ifup6 wan6 to restart your wan6 interface
  - use ifstatus wan6 to check if you still have an ipv6-address, ipv6-prefix (with assigned to lan entry), ipv6 dns-server
  - check again after 360s if still everything is fine

If everything to this point works, you should have at least a correct setup and working IPv6 connection. After that it makes sense to have a further look at your issue.
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More information can be found at the following URL:
https://bugs.lede-project.org/index.php?do=details&task_id=1002#comment3448