Can't ping from one machine to another (via NAT)

hello all helpers.

i have vmware server 1.0.6 on ubuntu 7.04 (i know it's not the newest systems.....)

i have one vm machine as astaro which have 4 network cards (1-bridge,3-NAT)

i have 3 more machine(DB,APP,WEB) with win-server 2000 that have 1 card each (all connect as NAT)

the problem:

i try to ping from DB to astaro - not working.

i try to ping from astaro to DB - works.

if i try pinging again from DB to astaro (after the astaro->DB ping) it works also, and i can get to the internet from DB (via the astaro)

after few minutes the connection is dead again.no internet,no ping.

here is ipconfig /all from DB

Windows 2000 IP Configuration

        Host Name . . . . . . . . . . . . : MSD-DB

        Primary DNS Suffix  . . . . . . . :

        Node Type . . . . . . . . . . . . : Broadcast

        IP Routing Enabled. . . . . . . . : No

        WINS Proxy Enabled. . . . . . . . : No

Ethernet adapter Local Area Connection 3:

        Connection-specific DNS Suffix  . :

        Description . . . . . . . . . . . : VMware Accelerated AMD PCNet Adapter

        Physical Address. . . . . . . . . : 00-0C-29-12-F8-1F

        DHCP Enabled. . . . . . . . . . . : No

        IP Address. . . . . . . . . . . . : 192.10.20.2

        Subnet Mask . . . . . . . . . . . : 255.255.255.0

        Default Gateway . . . . . . . . . : 192.10.20.254

        DNS Servers . . . . . . . . . . . : 192.10.20.254

the astaro ifconfig -a is attached as image (sorry, i'm not too familiar with linux..)

eth0 is supposed to be the DB gateway

eth1 is connected to the outside net(brigde)

eth2, eth3 are for the APP and WEB servers.