virtualbox.org

Running virtual box 4.3.26 on win 7 with an ubuntu 14.04 server running in headless mode.
Sometimes i cant not reach the unbutu server from other clients on my network on any protocol (but not seen the issues from other networks (internet)). However if i manage to connect to the ubuntu server and ping another host that host can then communicate on all available protocols, not just the one i initiated with (usually ping). Also i can never contact the host virtualbox machine via IP, although i can ping it from the ubuntu server?
sounds firewallish except for he fact that i can start to use all protocols one the host has been pinged, and sometimes it just works ok, not sure it it has done some type of broadcast?

Any ideas ?

Andrew

Got a little further,
The reason is the arp broadcasts don't appear to be working , if pinging the client works then the arp table is updated at both ends, or if the entries are added to the arp tables manually on ubuntu server then it also works ok.
Any idea why the arp cache (which i have cleared down and refreshed) is not being updated properly