VirtualBox VM cannot 'see' bridged host

[Dos_Box]

A bit of a stange one this that will probably have a really easy solution, but I can't see the wood fro the trees I suspect.
I'm doign some testing of systems management/monitoring software and have setup an old XP VM to be the host for these. As it would need to be on our small office LAN to demoinstate features I have set the VM NIC to bridged mode i.e. it will recive a DHCP address from the server and be on the same range as all of the other office hardware.
This went fine until I discovered tha the only thing it cannot see is the host machine (my desktop PC). I can ping all of the other office harware such as the SAN, router, switch etc, but not the host machine. And neither can I ping the VM from the host. It is most perplexing, so any help would be much appreciated.
Oh, and the office router (a Netgear WNR2000) handles DHCP, DNS etc.

[Dos_Box]

Ah, got it. The Windows XP VM firewall was blocking traffic (I can ping the VM when it is disabled) and it appears the W7 hosts firewall is doing the same (the VM cannot ping the host). It's config time!

[nephilim]

How are the firewalls set up? Are you using the standard Windows Firewall?

[Dos_Box]

Yes, I'm using Windows firewalls (XP and 7). However I now suspect the issue is a combination of things. I'll post back when I have a more thourough answer.

[nephilim]

The firewalls themselves shouldn't be blocking all of the traffic unless it has closed all of the ports...are the "ports" open on the VMs?

Sorry to ask questions but I have never come across this myself and its interesting to note whats happening so I can learn

[Dos_Box]

I've got it narrowed down to W7 as I've now tried to install The Dude on there and it fails to see any clients whatsoever; and yes, I've installed the SNMP service
All firewall settigns are default and the W7 install is less than 3 weeks old. Much of a puzzler this one.

[ChrisH]

What network profile has it associated itself to eg public, private etc?

[nephilim]

Chris_H beat me too it...if it is set to home, change it to work, and vice versa, if set to public, set it to work.

After that, turn off the firewall and try, and add in the firewall filters as needed.