TCP and UDP network communication problems

[cpschnuffel]

Hi there,
I use an XP SP3 guest under an XP SP3 host. The guest's network interface is set to "bridged" to the host's network interface card which is connected to my network. A router with a built-in DHCP server is attached to this network. Over this router my network devices are connected to the internet.

My first problem: When my guest tries to dynamically receive an IP address from this DHCP server, it fails. The DHCP server itself works, because another PC is retrieving its IP address without any problems. To avoid this problem, I momentarily use a static IP which fits the IP range of my network (192.168.16.x). But of course I'm interested in solving this problem.

My second problem: My guest only has internet access when I use "NAT" instead of "bridged" for its network interface. I don't understand this, because the manual says that "bridged" is like a software network adapter and the guest then appears and works as fully-equipped network device.

I'm able to ping my guest from other network devices. I'm also able to access a network folder on my guest from other network devices (but only as "\\<IP address>\<folder name>", NOT as "\\<Virtual PC name>\<folder name>"). The guest's firewall is disabled.

My main problem: I am NOT able to set up a simple TCP or UDP connection from the guest to a network device other than the host or vice versa (I often have to communicate with measurement devices via USB or ethernet, and so it's important for me to have this access from within my guest). TCP and UDP communication between host and guest is no problem. For this tests I use the Docklight Scripting evaluation version (http://www.docklight.de) which allows me to open TCP and UDP connections on single ports.

The test results are as follows:

TCP from guest to host and vice versa -> OK
UDP from guest to host and vice versa -> OK

TCP from host to a network PC and vice versa -> OK
UDP from host to a network PC and vice versa -> OK

TCP from guest to this network PC and vice versa -> FAILED
UDP from guest to this network PC and vice versa -> FAILED


Any idea is appreciated!

Regards from Berlin/Germany
cpschnuffel

[BillG]

That sounds like your bridged mode networking is not operating correctly. I would shut down all the vms and do a repair install of VirtualBox to see it clears the problem with the filter driver. (The filter driver is installed in the host OS so that the physical and virtual machines can both use the physical NIC in the host machine).

[cpschnuffel]

Hi BillG,
you hit the bull's eye! 12 Points for you !!!!
(I have completely reinstalled VirtualBox)

Carsten