Router1
ipv6 address print
Flags: X - disabled, I - invalid, D - dynamic, G - global, L - link-local
 #    ADDRESS                                     FROM-POOL INTERFACE   ADVERTISE
 0 DL fe80::d6ca:6dff:fe44:63f8/64                          ether13     no
 1 DL fe80::d6ca:6dff:fe44:63ec/64                          ether1      no
 2 DL fe80::b2fa:8d0c/64                                    sit1        no
 3  G 2001:470:1f1a:2fc::2/64                               sit1        no
 4  G 2001:470:1f1b:2f1c::1/64                              ether1      yes

Host1
ifconfig
enp2s0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet6 2001:470:1f1b:2f1c:21d:60ff:fe04:a223  prefixlen 64  scopeid 0x0<global>
        inet6 fe80::21d:60ff:fe04:a223  prefixlen 64  scopeid 0x20<link>
        ether 00:1d:60:04:a2:23  txqueuelen 1000  (Ethernet)
        RX packets 440  bytes 66844 (65.2 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 265  bytes 66331 (64.7 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
ip -6 route
::/64 dev enp2s0  proto ra  metric 100
2001:470:1f1b:2f1c::/64 dev enp2s0  proto ra  metric 100
fe80::/64 dev enp1s2  proto kernel  metric 256
fe80::/64 dev enp2s0  proto kernel  metric 256
default via fe80::d6ca:6dff:fe44:63ec dev enp2s0  proto static  metric 100