Re: Ipv6 - Cannot ping ipv6 lan nodes after 'wg-quick up config_file'

[Allen <eawalker@pm.me>]

BTW here's my setup with wireguard up:

http://ix.io/1fks

On 6/26/2018 12:58 PM, Allen wrote:
> Problem: Bringing up wireguard via wq-quick causes pings to lan clients
> to fail. Ip4 has no issues. Ultimately I think this is breaking LAN
> client routing ipv6 packets thru my route (single board computer/rasp
> pi) device. I need to fix my ipv6 routing table but don't know how.
> Here's some info:
>
> # wg-quick up mullvad-us1
> [#] ip link add mullvad-us1 type wireguard
> [#] wg setconf mullvad-us1 /dev/fd/63
> [#] ip address add 10.99.XX.XXX/32 dev mullvad-us1
> [#] ip address add fc00:bbbb:bbbb:bb01::XXXX/128 dev mullvad-us1
> [#] ip link set mtu 1420 dev mullvad-us1
> [#] ip link set mullvad-us1 up
> [#] resolvconf -a tun.mullvad-us1 -m 0 -x
> [#] wg set mullvad-us1 fwmark 51820
> [#] ip -6 route add ::/0 dev mullvad-us1 table 51820
> [#] ip -6 rule add not fwmark 51820 table 51820
> [#] ip -6 rule add table main suppress_prefixlength 0
> [#] ip -4 route add 0.0.0.0/0 dev mullvad-us1 table 51820
> [#] ip -4 rule add not fwmark 51820 table 51820
> [#] ip -4 rule add table main suppress_prefixlength 0
>
> Ping a LAN ipv6 client FAILS
>
> # ping fd00::ba27:ebff:feeb:a757
> PING fd00::ba27:ebff:feeb:a757(fd00::XXXX:ebff:feeb:XXXX) 56 data bytes
> ^C
> --- fd00::XXXX:ebff:feeb:XXXX ping statistics ---
> 6 packets transmitted, 0 received, 100% packet loss, time 5013ms
>
> Take wireguard down:
>
> # wg-quick down mullvad-us1
> [#] ip -4 rule delete table 51820
> [#] ip -4 rule delete table main suppress_prefixlength 0
> [#] ip -6 rule delete table 51820
> [#] ip -6 rule delete table main suppress_prefixlength 0
> [#] ip link delete dev mullvad-us1
> [#] resolvconf -d tun.mullvad-us1
>
> Ping a LAN ipv6 client SUCCEEDS
>
> # ping fd00::ba27:ebff:feeb:a757
> PING fd00::ba27:ebff:feeb:a757(fd00::XXXX:ebff:feeb:XXXX) 56 data bytes
> 64 bytes from fd00::XXXX:ebff:feeb:XXXX: icmp_seq=3D1 ttl=3D64 time=3D0.8=
84 ms
> 64 bytes from fd00::XXXX:ebff:feeb:XXXX: icmp_seq=3D2 ttl=3D64 time=3D0.8=
81 ms
> ^C
> --- fd00::XXXX:ebff:feeb:XXXX ping statistics ---
> 2 packets transmitted, 2 received, 0% packet loss, time 1001ms
> rtt min/avg/max/mdev =3D 0.881/0.882/0.884/0.029 ms
>
>
> SYSTEM CONFIGURATION:
>
> # uname -ra
> Linux DietPi 3.16.56+ #1 SMP PREEMPT Wed Apr 18 16:59:34 CEST 2018
> aarch64 GNU/Linux
>
> # cat /proc/sys/net/ipv6/conf/all/forwarding
> 1
>
> # cat /etc/os-release
> PRETTY_NAME=3D"Debian GNU/Linux 9 (stretch)"
> NAME=3D"Debian GNU/Linux"
> VERSION_ID=3D"9"
> VERSION=3D"9 (stretch)"
> ID=3Ddebian
> HOME_URL=3D"https://www.debian.org/"
> SUPPORT_URL=3D"https://www.debian.org/support"
> BUG_REPORT_URL=3D"https://bugs.debian.org/"
>
> radvd.conf:
>
> interface eth0 {
>   =C2=A0=C2=A0=C2=A0=C2=A0 AdvSendAdvert on;
>   =C2=A0=C2=A0=C2=A0=C2=A0 MinRtrAdvInterval 3;
>   =C2=A0=C2=A0=C2=A0=C2=A0 MaxRtrAdvInterval 10;
>   =C2=A0=C2=A0=C2=A0=C2=A0 AdvDefaultPreference high;
>   =C2=A0=C2=A0=C2=A0=C2=A0 prefix fd00::/64 {
>   =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 AdvOnLink on;
>   =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 AdvAutonomous on=
;
>   =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 AdvRouterAddr on=
;
>   =C2=A0=C2=A0=C2=A0=C2=A0 };
>   =C2=A0=C2=A0=C2=A0=C2=A0 RDNSS fd00::1 {};
> };
>
> # cat /etc/network/interfaces
> #/etc/network/interfaces
> #Please use DietPi-Config to modify network settings.
>
> # Local
> auto lo
> iface lo inet loopback
>
> # Ethernet
> allow-hotplug eth0
> iface eth0 inet static
> address 192.168.2.4
> netmask 255.255.255.0
> gateway 192.168.2.1
> dns-nameservers 127.0.0.1 8.8.8.8
>
> iface eth0 inet6 static
> address fd00::1
> netmask 64
>
> # cat /etc/wireguard/mullvad-us1.conf
> [Interface]
> PrivateKey =3D XXXXXXXXXXXXXXXXXXXX
> Address =3D 10.99.XX.XXX/32,fc00:bbbb:bbbb:bb01::XXXX/128
> DNS =3D 8.8.8.8
> PostUp =3D iptables -A FORWARD -i %i -j ACCEPT; iptables -A FORWARD -o %i
> -j ACCEPT; iptables -t nat -A POSTROUTING -o %i -j MASQUERADE; ip6tables
> -t nat -A POSTROUTING -s fd00::/64 -o %i -j SNAT --to-source
> fc00:bbbb:bbbb:bb01::XXXX
> PostDown =3D iptables -D FORWARD -i %i -j ACCEPT; iptables -D FORWARD -o
> %i -j ACCEPT; iptables -t nat -D POSTROUTING -o %i -j
> MASQUERADE;ip6tables -t nat -D POSTROUTING -s fd00::/64 -o %i -j SNAT
> --to-source fc00:bbbb:bbbb:bb01::XXXX
>
>
>
> [Peer]
> PublicKey =3D XXXXXXXXXXXXXXXXXXXX
> Endpoint =3D 185.232.XX.XX:51820
> AllowedIPs =3D 0.0.0.0/0, ::/0
>
> Wireguard down:
>
> #ip -d -6 route
> unicast fd00::/64 dev eth0 proto kernel scope global metric 256
> unicast fe80::/64 dev eth0 proto kernel scope global metric 256
>
> Wireguard up:
>
> # ip -d -6 route
> unicast fc00:bbbb:bbbb:bb01::XXXX dev mullvad-us1 proto kernel scope
> global metric 256
> unicast fd00::/64 dev eth0 proto kernel scope global metric 256
> unicast fe80::/64 dev eth0 proto kernel scope global metric 256
>
>
> With wireguard up, if I try to see the route taken to my lan ping I
> see it's trying to go thru mullvad-us1 which logically is incorrect:
>
> # ip -s route get fd00::XXXX:ebff:feeb:XXXX
> fd00::XXXX:ebff:feeb:XXXX from :: dev mullvad-us1 table 51820 src
> fc00:bbbb:bbbb:bb01::XXXX metric 0
>   =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 cache=C2=A0 users 1 used 1
>
> No problems pinging google though:
>
> # ping -6 google.com
> PING google.com(lga25s56-in-x0e.1e100.net (2607:f8b0:4006:800::200e)) 56
> data bytes
> 64 bytes from lga25s56-in-x0e.1e100.net (2607:f8b0:4006:800::200e):
> icmp_seq=3D1 ttl=3D54 time=3D41.1 ms
> 64 bytes from lga25s56-in-x0e.1e100.net (2607:f8b0:4006:800::200e):
> icmp_seq=3D2 ttl=3D54 time=3D41.1 ms
> ^C
> --- google.com ping statistics ---
> 2 packets transmitted, 2 received, 0% packet loss, time 1001ms
> rtt min/avg/max/mdev =3D 41.144/41.153/41.162/0.009 ms
>
>
>