GitHub user tobzsc edited a discussion: EVPN-VXLAN - IPv6 via SLAAC
Hello everyone, we are still in the process of setting up our cloud environment and could use some advice. We are using BGP+EVPN+VXLAN in our setup, quite similar to how it's described here <https://vincent.bernat.ch/en/blog/2017-vxlan-bgp-evpn>. For this we're also using the modifyvxlan.sh script from here <https://gist.github.com/wido/51cb9880d86f08f73766634d7f6df3f4>. IPv4 works fine but we've hit a roadblock trying to set up IPv6. We've configured our Juniper routers to advertise a /64 in the same VNI that our VMs are in. However our VMs do not receive an IPv6 address. We have also manually tested using rdisc6 and that fails too. Testing on a physical host not connected via our EVPN+VXLAN fabric the host receives all RAs and successfully setups the IPv6 address. We have debugged this problem using tcpdump on the KVM host and found the following: - The router solicitation (RS) successfully exits the VM and we can see it on the physical interface - We can see the response - a router advertisement (RA) - on the **physical** interface - We can't see the same packet on the vxlan200 or brvx-200 interface. (It also never reaches the VM) Our conclusion was that the kernel must be dropping multicast packets somehow, but we're at a loss at figuring out why. quick tcpdump excerpt: ``` 13:38:59.971759 IP (tos 0x0, ttl 64, id 26030, offset 0, flags [none], proto UDP (17), length 98) 10.255.9.204.37206 > 10.255.11.1.4789: [bad udp cksum 0x2b2a -> 0xe4c9!] VXLAN, flags [I] (0x08), vni 200 IP6 (flowlabel 0xcdb3a, hlim 255, next-header ICMPv6 (58) payload length: 8) fe80::1c00:25ff:fe00:892 > ff02::2: [icmp6 sum ok] ICMP6, router solicitation, length 8 13:37:58.275395 IP (tos 0x0, ttl 63, id 58024, offset 0, flags [none], proto UDP (17), length 146) 10.255.11.1.39155 > 10.255.9.204.4789: [udp sum ok] VXLAN, flags [I] (0x0a), vni 200 IP6 (hlim 255, next-header ICMPv6 (58) payload length: 56) fe80::8ad9:8f00:c8f4:cc80 > ff02::1: [icmp6 sum ok] ICMP6, router advertisement, length 56 hop limit 64, Flags [none], pref medium, router lifetime 1800s, reachable time 0ms, retrans timer 0ms ``` Is anyone running a similar setup and has any advice, tips or ideas for us? Please let us know. Maybe we are just missing a kernel tweak or something. We are using CS 4.19 on AlmaLinux 9. GitHub link: https://github.com/apache/cloudstack/discussions/8685 ---- This is an automatically sent email for users@cloudstack.apache.org. To unsubscribe, please send an email to: users-unsubscr...@cloudstack.apache.org
