IPv6 enabled will grind network almost to a halt...

[jeekee]

Hi folks,

Trying to wrap my head around an issue I can't seem to pin down. I wanted to use ipv6 on my network (tried it couple a years ago and gave me a headache), setup up basic stuf without a problem. IPv6PD WAN gets LL address and on LAN track WAN interface and every vlan gets its own little piece of the ipv6 pie. Nothing fancy there. Unbound listens nicely to all interfaces on both ipv4 and ipv6. Also enabled tayga (and dns64 in unbound) just to be complete as my iot vlan is unfortunately not completely ipv6 and I wish my main vlan to be ipv6-only.

As soon as I disable ipv4 (or use the dhcp 108 to push my apple devices to ipv6) my loading times on websites increase significantly. Funny thing is that Facebook and instagram pretty much don't load any more or extremely slow (takes 30s). Can't figure out why. Ping6 to the outside world works. Funny thing is that traceroute6\UDP and ICMP seems to time out after several hops (for google sometimes it does sometimes it doesn't, for instagram it always times out after couple of hops). Tried several things to track down what was happening. Also tried to mess with MTU as I use a pppoe/vlan connection as advised elsewhere on the forum. Ifconfig shows mtu 1500 for the WAN so that would be okay (but could be wrong). Another thing that might be a possible tell tale is that RA gives the ll address of the router. If I manually change that on my MacBook to the gua address of my router most problems seem to disappear. But can't really wrap my head around that what might cause the issue.

Any ideas what's happening? Any help would be greatly appreciated as I am going crazy after debugging it for a week.

Kind regards, Jay

@Nevermind, rookie mistake. Switches weren't yet setup to handle ipv6 duh...

@@Okay http3/quic also seems to be an issue, blocking it all together made stuf like instagram run smooth again with ipv6.

@@@ problem seems to be slaac related. If is switch to dhcpv6 i never get buffering issues and as soon as i switch to anything with slaac it grinds down the connectivity. Seems to be a sort of known issue with ios devices on slaac. Apparently the slaac rdnss with time 1800 and device goes to sleep it looses its dns server. So extending the time should fix it if you really want or need slaac. Will check if it fixes everything with slaac. At least dhcpv6 works😬