OS X 10.11.6 Fusion Pro 8.1.1 (3771013)
I've set up a custom vmnet configure as follows
With ipconfig -L on the host I get the following
vmnet6: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
ether 00:50:56:c0:00:06
inet 172.16.245.1 netmask 0xffffff00 broadcast 172.16.245.255
nd6 options=1<PERFORMNUD>
Seems odd that there is no IPv6 info but *shrug*
Static IPv6
There are two guest VMs running CentOS 7 (minimal install)
Box 1 : IPV6ADDR=fd15:4ba5:5a2b:1007::3
Box 2 : IPV6ADDR=fd15:4ba5:5a2b:1007::5
ping6 between them shows 100% packet loss, ssh times out. ssh from the host gives no route to host
Time to experiment with routing.
Added an IP to vmnet6 on the Host with 'sudo ifconfig vmnet6 inet6 fd15:4ba5:5a2b:1007::1 prefixlen 64' which gives me an ifconfig of
vmnet6: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
ether 00:50:56:c0:00:06
inet 172.16.245.1 netmask 0xffffff00 broadcast 172.16.245.255
inet6 fe80::250:56ff:fec0:6%vmnet6 prefixlen 64 scopeid 0xe
inet6 fd15:4ba5:5a2b:1007::1 prefixlen 64
nd6 options=1<PERFORMNUD>
Added the default GW to the guest machines (DEFROUTE did not work). IPV6_DEFAULTGW=fd15:4ba5:5a2b:1007::1%en16777736 to the ifcfg-en16777736
Still nothing between the guest machines however the host now shows ping6 fd15:4ba5:5a2b:1007::3
PING6(56=40+8+8 bytes) fd15:4ba5:5a2b:1007::1 --> fd15:4ba5:5a2b:1007::3 and a ping6 from guest to fd15:4ba5:5a2b:1007::1 works.
So we have do have a route there now. Progress! However it is not being picked up. Lets try advertising it.
sudo sysctl -w net.inet6.ip6.use_tempaddr=1
sudo sysctl -w net.inet6.ip6.forwarding=1
sudo rtadvd -sfD vmnet6 (-f for non-daemon, D for full debug)
Pings all around! Guests can ping each other, I can ssh into them from the host and ping that GW.... for about 100 seq numbers. Then the SSH pipe breaks, pings stop and everyone is unhappy again. If I restart rtadvd I get another success for about 100 seq numbers
Things seem to break right around the prefix check...
Aug 11 13:24:21 rtadvd[6744] <Info>: <getconfig> vmnet6 isn't defined in the configuration file or the configuration file doesn't exist. Treat it as default
Aug 11 13:24:21 rtadvd[6744] <Debug>: <get_prefix> add fd15:4ba5:5a2b:1007::/64 to prefix list on vmnet6
Aug 11 13:24:21 rtadvd[6744] <Debug>: <ra_timer_update> RA timer on vmnet6 is set to 0:0
Aug 11 13:24:21 rtadvd[6744] <Debug>: <ra_timeout> RA timer on vmnet6 is expired
Aug 11 13:24:21 rtadvd[6744] <Debug>: <ra_output> send RA on vmnet6, # of waitings = 0
Aug 11 13:24:21 rtadvd[6744] <Debug>: <ra_timer_update> RA timer on vmnet6 is set to 16:0
Aug 11 13:24:21 rtadvd[6744] <Debug>: <main> set timer to 16:0. waiting for inputs or timeout
Aug 11 13:24:21 rtadvd[6744] <Debug>: <ra_input> RA received from fe80::250:56ff:fec0:6 on vmnet6
Aug 11 13:24:21 rtadvd[6744] <Debug>: <main> set timer to 15:999740. waiting for inputs or timeout
Aug 11 13:24:37 rtadvd[6744] <Debug>: <ra_timeout> RA timer on vmnet6 is expired
Aug 11 13:24:37 rtadvd[6744] <Debug>: <ra_output> send RA on vmnet6, # of waitings = 0
Aug 11 13:24:37 rtadvd[6744] <Debug>: <ra_timer_update> RA timer on vmnet6 is set to 16:0
Aug 11 13:24:37 rtadvd[6744] <Debug>: <main> set timer to 16:0. waiting for inputs or timeout
Aug 11 13:24:37 rtadvd[6744] <Debug>: <ra_input> RA received from fe80::250:56ff:fec0:6 on vmnet6
Aug 11 13:24:37 rtadvd[6744] <Debug>: <main> set timer to 15:999108. waiting for inputs or timeout
Aug 11 13:24:38 rtadvd[6744] <Debug>: <ra_input> RA received from fe80::250:56ff:fec0:2222 on vmnet6
Aug 11 13:24:38 rtadvd[6744] <Info>: <nd6_options> unknown ND option(type 24)
Aug 11 13:24:38 rtadvd[6744] <Info>: <prefix_check> preferred lifetime for fd15:4ba5:5a2b:1007::/64 inconsistent on vmnet6: 14400 from fe80::250:56ff:fec0:2222, 604800 from us
Aug 11 13:24:38 rtadvd[6744] <Info>: <prefix_check> valid lifetime for fd15:4ba5:5a2b:1007::/64 inconsistent on vmnet6: 86400 from fe80::250:56ff:fec0:2222, 2592000 from us
Aug 11 13:24:38 rtadvd[6744] <Debug>: <main> set timer to 15:295751. waiting for inputs or timeout
Anyone able to give any help in regards to this? The RA from fe80 is odd, and I have tried setting explicit pltime 14400 vltime 86400 to no effect.
Update : If I leave things alone (with rtadv running) Every once in a while about 20 pings will succeed, then start failing again)
Hi AdrianMulvaney74,
Thanks for reporting this. We already have bug to track this. 
Thanks,
Nancy