Bridged Connection weird IP release in the NAT router

Hi, I use Vmware Player 6.0.2 to run linux on my linux machine with no vmware tools. Both linuxes are Slackware 14.1. In my guest system I have a web-server with bridged connection. Both, host and guest, appear with same MAC address and different IPs in my NAT router (self assigned). After some amount of time ( ~16 hours last time) the IP of the guest 'disappears' from the router and my web-server becomes unreachable. Going to the guest and executing wget or opening a page with the browser returns the NAT IP for the guest on the router.

Is it because of some kind of inactivity on my guest slackware?

Or is it specific to vmware bridged connection?

Thanks!