Hi, [Somewhat off-topic, since this is a general networking topic:]
I have Verizon Fios residential internet service. Verizon is notoriously cagey about its deployment of IPv6 for residential service [1], but I don't seem to officially have it - my router (running OpenWrt) tries dhcp6 but fails to get anything, and all the router's interfaces show only link-local addresses for IPv6. I noticed, however, that when I try to connect to the router over the public internet via a DDNS hostname tied to the router's external IPv4 address, the connections take place via IPv6! I dug (no pun intended) a bit further, and found this (where a.b.c.d is my Verizon-assigned (via dhcp) dotted-quad IPv4 address): ~$ host a.b.c.d d.c.b.a.in-addr.arpa domain name pointer pool-a-b-c-d.region.fios.verizon.net. (where 'region' is my geographic region). ~$ host pool-a-b-c-d.region.fios.verizon.net pool-a-b-c-d.region.fios.verizon.net has address a.b.c.d pool-a-b-c-d.region.fios.verizon.net has IPv6 address e:f:g:h:i:j:k:l So lo and behold, I do seem to have an IPv6 address, and this address e:f:g:h:i:j:k:l is indeed the one that my clients are using to reach the router (xxx.yyy.zzz is the DDNS hostname): ~$ ping xxx.yyy.zzz PING xxx.yyy.zzz(pool-a-b-c-d.region.fios.verizon.net (e:f:g:h:i:j:k:l)) 56 data bytes 64 bytes from pool-a-b-c-d.region.fios.verizon.net (e:f:g:h:i:j:k:l): icmp_seq=1 ttl=51 time=29.1 ms But the IPv6 address e:f:g:h:i:j:k:l is not actually configured anywhere on the router (as shown by 'ip a' and other tools)! Is this really how IP works, that since Verizon is sending packets with that destination down my connection, my router is going to accept and reply to them despite not having any such IP address configured? [1] https://www.verizon.com/support/residential/internet/getting-started/learn-about-ipv6 https://www.dslreports.com/forum/r32136440-Networking-IPv6-working Celejar
