This is simplified example, so it may sound silly.
I have openSuse 13.1 as host with virtualbox 5.0.26 and two guests openSuse 13.2.
And setup like this. PC B is connected by internal network to PC A. PC A has bridge over both eths (brctl). And PC A (eth1) is attached to physical eth of PC2 (host) like "bridge adapter". PC1 is connected to PC2 - utp.
And there is situation. Ping from PC B to PC1 (both in same network). ARP request passed clearly from PC B to PC1. PC1 send ARP reply. I can see packet "ARP reply" on physical eth of PC2 (host), but on eth1 PC A never appears. So ping failed.
Some more info:
- without PC A everything working fine (physical eth of PC2 attached to PC B like bridge adapter)
- I tried all adapter types and connection is ok only with PCnet-FAST II and PCnet-FAST III
- Everywhere is installed wireshark.
- Allowed ip forward on host is not helping. Even I try allow ip forward on PC A.
thanks for any ideas