> When I try to ping an IPv6 address (like example.com’s IP 2606:2800:220:1:248:1893:25c8:1946 for example) I get the error ping: connect: Network is unreachable. Why? (answer: it’s because my ISP doesn’t support IPv6 so my computer doesn’t have a public IPv6 address)

    $ ssh freenas.local
    freenas$ ping6 2606:2800:220:1:248:1893:25c8:1946
    ping6: UDP connect: No route to host

    freenas$ ping6 2606:2800:220:1:248:1893:25c8:1946
    PING6(56=40+8+8 bytes) 2600:1700:3d40:6300:6a05:caff:fe58:a370 --> 2606:2800:220:1:248:1893:25c8:1946
    16 bytes from 2606:2800:220:1:248:1893:25c8:1946, icmp_seq=0 hlim=54 time=11.408 ms

(AT&T is my ISP and it took a bit of screwing around over a weekend with my router a couple years ago to get IPv6 working properly on my home network. But it's been painless ever since.)

If you like tinkering and you've got the AT&T fiber service and don't use the voice/TV U-Verse stuff) you can get significantly better IPv4 and IPv6 performance not using their gateway (even if it's just in bridge mode with every service disabled). It's not officially supported and they actually 802.1x auth the modem but there are convenient scripts out there to proxy the auth packets allowing you to use your own router directly. Particularly helpful for maxing out their gig service or for drastically improving jitter at any service speed.

AT&T has transitioned to issuing a combined ONT/Router, where this will no longer be possible, but apparently the newer gear doesn't have any of the performance issues of the Pace 5268AC.

BTW, I was annoyed that AT&T installed the ONT on the southern wall of my home where it was baking in full sun everyday, so I relocated it myself into my network closet. You can just unplug the ONT and extend the existing fiber with an optical coupler and an SC-APC to SC-APC single-mode patch cable.