Cant ping/access IPv6 but somehow I can ssh/ping my VM using its IPv6???

Otus9051

So my network setup is something like this:

2: enp6s18: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 26:19:bc:a4:78:92 brd ff:ff:ff:ff:ff:ff
    inet 165.140.142.92/24 brd 165.140.142.255 scope global enp6s18
       valid_lft forever preferred_lft forever
    inet6 2a12:dd47:da63:6c61:7373::/64 scope global 
       valid_lft forever preferred_lft forever
    inet6 2602:fc23:18::2b/64 scope global 
       valid_lft forever preferred_lft forever
    inet6 fe80::2419:bcff:fea4:7892/64 scope link 
       valid_lft forever preferred_lft forever
3: enp6s19: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 9000 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 00:05:69:10:3a:46 brd ff:ff:ff:ff:ff:ff
    inet 185.0.19.42/24 scope global enp6s19
       valid_lft forever preferred_lft forever
    inet6 2001:7f8:2:1::3:c0d/64 scope global 
       valid_lft forever preferred_lft forever
    inet6 2001:7f8:2:1:205:69ff:fe10:3a46/64 scope global dynamic mngtmpaddr noprefixroute 
       valid_lft 2591497sec preferred_lft 604297sec
    inet6 fe80::205:69ff:fe10:3a46/64 scope link 
       valid_lft forever preferred_lft forever

Now, enp6s18 is facing the public web and enp6s19 is connected to GPC (no Public Internet).
When I try to ping a IPv6 IP, this happens:

ping -6 google.com
PING google.com(jq-in-f102.1e100.net (2607:f8b0:4001:c03::66)) 56 data bytes
^C
--- google.com ping statistics ---
19 packets transmitted, 0 received, 100% packet loss, time 18411ms

Pinging from enp6s18 specifically does this:

ping -6 google.com -I enp6s18
ping: google.com: Address family for hostname not supported

Explicitly specifying IP:

ping 2607:f8b0:4001:c03::66 -I enp6s18
ping: connect: Network is unreachable

TL;DR: Can't access IPv6 from VM but can access VM from IPv6. It seems that everything is taking enp6s19 as default even when I explicitly mention it.

traceroute doesnt work:

traceroute ipv6.google.com -i enp6s18
traceroute to ipv6.google.com (2607:f8b0:4001:c1d::65), 30 hops max, 80 byte packets
connect: Network is unreachable

MTR does but it uses 2a12:dd47:da63:6c61:7373::/64 which is fine, i guess.

Otus9051

Found the problem -- everything is going through

default via fe80::4288:2fff:febf:2662 dev enp6s19 proto ra metric 100 expires 1534sec mtu 1500 pref medium

yoursunny

Check your routes:

ip -6 rule list
ip -6 route list table all type unicast

Otus9051

Fixed it with sudo ip -6 route add default via 2602:fc23:18::1 dev enp6s18