我發現我 ping host 不會通，感覺這個解決了就通了：
$ ping6 fe80::5fe4:5829:d90:77b1
PING6(56=40+8+8 bytes) fe80::1cae:ff43:7abe:2627%en0 --> fe80::5fe4:5829:d90:77b1
ping6: sendmsg: No route to host
ping6: wrote fe80::5fe4:5829:d90:77b1 16 chars, ret=-1
ping6: sendmsg: No route to host
ping6: wrote fe80::5fe4:5829:d90:77b1 16 chars, ret=-1
ping6: sendmsg: No route to host
ping6: wrote fe80::5fe4:5829:d90:77b1 16 chars, ret=-1
ping6: sendmsg: No route to host
ping6: wrote fe80::5fe4:5829:d90:77b1 16 chars, ret=-1
ping6: sendmsg: No route to host
ping6: wrote fe80::5fe4:5829:d90:77b1 16 chars, ret=-1
ping6: sendmsg: No route to host
ping6: wrote fe80::5fe4:5829:d90:77b1 16 chars, ret=-1
ping6: sendmsg: No route to host
ping6: wrote fe80::5fe4:5829:d90:77b1 16 chars, ret=-1
ping6: sendmsg: No route to host
ping6: wrote fe80::5fe4:5829:d90:77b1 16 chars, ret=-1
^C
--- fe80::5fe4:5829:d90:77b1 ping6 statistics ---
8 packets transmitted, 0 packets received, 100.0% packet loss