Unable to ping guest from host in host-only network; ping6 works

[Rick]

An environment with a VM that has 2 types of networks: 1 NAT, 1 Host-Only
NAT works fine for world access but for internal access to the host, the IPv4 is not working even though IPv6 works fine

The host is running MacOSX 10.7.5
The Guest is an Ubuntu 11.10

Host virtual switches

vboxnet0: flags=8842<BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
	ether 0a:00:27:00:00:00
vboxnet1: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500 
	ether 0a:00:27:00:00:01
	inet 10.100.100.1 netmask 0xffffff00 broadcast 10.100.100.255
	inet6 fe80::800:27ff:fe00:1%vboxnet1 prefixlen 64 scopeid 0x9  
	inet6 2000:aaaa::1 prefixlen 64

Ping6 test from host to guest

nightwatch:~ ricky$ ping6 2000:aaaa::2
PING6(56=40+8+8 bytes) 2000:aaaa::1 --> 2000:aaaa::2
16 bytes from 2000:aaaa::2, icmp_seq=0 hlim=64 time=155.398 ms
16 bytes from 2000:aaaa::2, icmp_seq=1 hlim=64 time=0.715 ms
16 bytes from 2000:aaaa::2, icmp_seq=2 hlim=64 time=1.023 ms
16 bytes from 2000:aaaa::2, icmp_seq=3 hlim=64 time=0.840 ms
16 bytes from 2000:aaaa::2, icmp_seq=4 hlim=64 time=0.929 ms
16 bytes from 2000:aaaa::2, icmp_seq=5 hlim=64 time=0.875 ms 
16 bytes from 2000:aaaa::2, icmp_seq=6 hlim=255 time=0.909 ms
16 bytes from 2000:aaaa::2, icmp_seq=7 hlim=255 time=0.873 ms
16 bytes from 2000:aaaa::2, icmp_seq=8 hlim=255 time=0.864 ms
16 bytes from 2000:aaaa::2, icmp_seq=9 hlim=255 time=0.739 ms
16 bytes from 2000:aaaa::2, icmp_seq=10 hlim=255 time=0.756 ms
16 bytes from 2000:aaaa::2, icmp_seq=11 hlim=255 time=1.067 ms
^C
--- 2000:aaaa::2 ping6 statistics ---
12 packets transmitted, 12 packets received, 0.0% packet loss
round-trip min/avg/max/std-dev = 0.715/13.749/155.398/42.709 ms

Ping Test from Host to Guest

nightwatch:~ ricky$ ping 10.100.100.2
PING 10.100.100.2 (10.100.100.2): 56 data bytes
Request timeout for icmp_seq 0
Request timeout for icmp_seq 1
^C
--- 10.100.100.2 ping statistics ---
3 packets transmitted, 0 packets received, 100.0% packet loss
nightwatch:~ ricky$ 

Guest Network Configuration

ricky@bunker:~$ ifconfig
eth0      Link encap:Ethernet  HWaddr 08:00:27:41:4f:1b
          inet addr:10.0.2.15  Bcast:10.0.2.255  Mask:255.255.255.0
          inet6 addr: fe80::a00:27ff:fe41:4f1b/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:2 errors:0 dropped:0 overruns:0 frame:0
          TX packets:29 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:1180 (1.1 KB)  TX bytes:2240 (2.2 KB)
eth1      Link encap:Ethernet  HWaddr 08:00:27:9d:08:1d
          inet addr:10.100.100.2  Bcast:0.0.0.0  Mask:255.255.255.0
          inet6 addr: fe80::a00:27ff:fe9d:81d/64 Scope:Link
          inet6 addr: 2000:aaaa::2/64 Scope:Global
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:168 errors:0 dropped:0 overruns:0 frame:0
          TX packets:238 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:20887 (20.8 KB)  TX bytes:23841 (23.8 KB)
lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)
pimreg    Link encap:UNSPEC  HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00
          UP RUNNING NOARP  MTU:1472  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

Ping6 Test from guest to Host

ricky@bunker:~$ ping6 2000:aaaa::1
PING 2000:aaaa::1(2000:aaaa::1) 56 data bytes
64 bytes from 2000:aaaa::1: icmp_seq=1 ttl=64 time=0.317 ms
64 bytes from 2000:aaaa::1: icmp_seq=2 ttl=64 time=0.518 ms
^C
 2000:aaaa::1 ping statistics
2 packets transmitted, 2 received, 0% packet loss, time 1001ms
rtt min/avg/max/mdev = 0.317/0.417/0.518/0.102 ms
ricky@bunker:~$ ^C

[Valery Ushakov]

Is this still a problem? Have you used Cisco AnyConnect VPN on the host by any chance (#14293)?

If this is still a problem, please, provide routing info for the host and for the guest and a packet capture on eth1 from the guest.