old_router

/home/root # ip -6 route
2a0d:8340:1572::/64 dev br0  proto kernel  metric 256
2a0d:8340:1572::/64 via :: dev sit1  proto kernel  metric 256
fe80::/64 dev br0  proto kernel  metric 256
fe80::/64 dev eth3  proto kernel  metric 256
fe80::/64 dev apclii0  proto kernel  metric 256
fe80::/64 via :: dev sit1  proto kernel  metric 256  mtu 1280
default via 2a0d:8340:1572::1 dev sit1  metric 1

/home/root # ip a show br0
7: br0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP
    link/ether 50:d2:f5:28:d9:5e brd ff:ff:ff:ff:ff:ff
    inet 192.168.19.1/24 brd 192.168.19.255 scope global br0
    inet6 2a0d:8340:1572::/64 scope global
       valid_lft forever preferred_lft forever
    inet6 fe80::52d2:f5ff:fe28:d95e/64 scope link
       valid_lft forever preferred_lft forever

/home/root # ip a show sit1
20: sit1: <POINTOPOINT,NOARP,UP,LOWER_UP> mtu 1280 qdisc noqueue state UNKNOWN
    link/sit 192.168.6.200 peer 193.0.203.203
    inet6 2a0d:8340:1572::2/64 scope global
       valid_lft forever preferred_lft forever
    inet6 fe80::c0a8:6c8/128 scope link
       valid_lft forever preferred_lft forever