Below is my environment:

I have 1 physical machine running Windows 2008 R2, with the Hyper-V role. This machine has 3 physical NICs:

• One for Internet
• One for Internal Network
• One for Wireless Network

All 3 have their respective Virtual Networks in Hyper-V, and I have an extra Private virutal machine network for a DMZ Network.
In one of the virtual machines, I have TMG Forefront 2010 SP1 installed, with all 4 networks available to it. Below is the IPCONFIG /ALL at the firewall:

Windows IP Configuration

   Host Name . . . . . . . . . . . . : FRW-EXP1-02
   Primary Dns Suffix  . . . . . . . : exp1.eti.br
   Node Type . . . . . . . . . . . . : Hybrid
   IP Routing Enabled. . . . . . . . : Yes
   WINS Proxy Enabled. . . . . . . . : No
   DNS Suffix Search List. . . . . . : exp1.eti.br

Ethernet adapter Internet:

   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : Microsoft Virtual Machine Bus Network Adapter #4
   Physical Address. . . . . . . . . : 00-15-5D-01-06-0E
   DHCP Enabled. . . . . . . . . . . : Yes
   Autoconfiguration Enabled . . . . : Yes
   Link-local IPv6 Address . . . . . : fe80::6d05:6033:4cfc:bdf5%15(Preferred)
   IPv4 Address. . . . . . . . . . . : 189.100.110.xxx(Preferred)
   Subnet Mask . . . . . . . . . . . : 255.255.240.0
   Lease Obtained. . . . . . . . . . : quarta-feira, 5 de janeiro de 2011 11:17:24
   Lease Expires . . . . . . . . . . : quarta-feira, 5 de janeiro de 2011 16:07:02
   Default Gateway . . . . . . . . . : 189.100.96.xxx
   DHCP Server . . . . . . . . . . . : 201.6.2.43
   DHCPv6 IAID . . . . . . . . . . . : 436213085
   DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-14-6D-75-6F-00-15-5D-01-06-0B
   DNS Servers . . . . . . . . . . . : 201.6.2.163
                                       201.6.2.43
   NetBIOS over Tcpip. . . . . . . . : Enabled

Ethernet adapter Rede Interna:

   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : Microsoft Virtual Machine Bus Network Adapter #3
   Physical Address. . . . . . . . . : 00-15-5D-01-06-0C
   DHCP Enabled. . . . . . . . . . . : No
   Autoconfiguration Enabled . . . . : Yes
   Link-local IPv6 Address . . . . . : fe80::51ff:4723:ce4c:bbc3%14(Preferred)
   IPv4 Address. . . . . . . . . . . : 10.50.75.10(Preferred)
   Subnet Mask . . . . . . . . . . . : 255.255.255.0
   Default Gateway . . . . . . . . . :
   DHCPv6 IAID . . . . . . . . . . . : 352327005
   DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-14-6D-75-6F-00-15-5D-01-06-0B
   DNS Servers . . . . . . . . . . . : 10.50.75.1
                                       10.50.75.2
   NetBIOS over Tcpip. . . . . . . . : Enabled

Ethernet adapter DMZ:

   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : Microsoft Virtual Machine Bus Network Adapter #2
   Physical Address. . . . . . . . . : 00-15-5D-01-06-0A
   DHCP Enabled. . . . . . . . . . . : No
   Autoconfiguration Enabled . . . . : Yes
   Link-local IPv6 Address . . . . . : fe80::d4c5:75cf:e9aa:73e1%13(Preferred)
   IPv4 Address. . . . . . . . . . . : 192.168.10.1(Preferred)
   Subnet Mask . . . . . . . . . . . : 255.255.255.0
   Default Gateway . . . . . . . . . :
   DHCPv6 IAID . . . . . . . . . . . : 301995357
   DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-14-6D-75-6F-00-15-5D-01-06-0B
   DNS Servers . . . . . . . . . . . : fec0:0:0:ffff::1%1
                                       fec0:0:0:ffff::2%1
                                       fec0:0:0:ffff::3%1
   NetBIOS over Tcpip. . . . . . . . : Enabled

Ethernet adapter Wireless:

   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : Microsoft Virtual Machine Bus Network Adapter
   Physical Address. . . . . . . . . : 00-15-5D-01-06-0B
   DHCP Enabled. . . . . . . . . . . : No
   Autoconfiguration Enabled . . . . : Yes
   Link-local IPv6 Address . . . . . : fe80::459:8ca6:d02:8da1%11(Preferred)
   IPv4 Address. . . . . . . . . . . : 192.168.1.10(Preferred)
   Subnet Mask . . . . . . . . . . . : 255.255.255.0
   Default Gateway . . . . . . . . . :
   DHCPv6 IAID . . . . . . . . . . . : 234886493
   DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-14-6D-75-6F-00-15-5D-01-06-0B
   DNS Servers . . . . . . . . . . . : fec0:0:0:ffff::1%1
                                       fec0:0:0:ffff::2%1
                                       fec0:0:0:ffff::3%1
   NetBIOS over Tcpip. . . . . . . . : Enabled

I have the Networks below at Forefront:

External: IP addresses external to the Forefront TMG Networks
Internal: 10.50.75.0 - 10.50.75.255
Local Host:
Perimiter: 192.168.10.0 - 192.168.10.255
Wireless: 192.168.1.0 - 192.168.1.255

In the Networks Rules, I have:

1 => Route => Local Host => All Networks
2 => Route => Quarantined; VPN => Internal
3 => NAT => Internal; VPN => Perimiter
4 => NAT => Internal; Perimiter; Quarantined; VPN; Wireless => External

My problem is that I can only communicate with the Internal and External networks. If a ping www.google.com or 10.50.75.21 from the Forefront VM, I get answer backs without a problem. If I try to ping a machine at the Perimiter network or the Wireless network, it doesn't get routed back to Forefront, and it's the default gateway on all Networks. Here as ping samples:

PS C:\Users\Administrator.TPB1> ping www.google.com

Pinging www.l.google.com [64.233.163.104] with 32 bytes of data:
Reply from 64.233.163.104: bytes=32 time=11ms TTL=58
Reply from 64.233.163.104: bytes=32 time=8ms TTL=58

Ping statistics for 64.233.163.104:
    Packets: Sent = 2, Received = 2, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 8ms, Maximum = 11ms, Average = 9ms
Control-C
PS C:\Users\Administrator.TPB1> ping 10.50.75.21

Pinging 10.50.75.21 with 32 bytes of data:
Reply from 10.50.75.21: bytes=32 time=1ms TTL=128
Reply from 10.50.75.21: bytes=32 time=1ms TTL=128
Reply from 10.50.75.21: bytes=32 time=1ms TTL=128
Reply from 10.50.75.21: bytes=32 time=1ms TTL=128

Ping statistics for 10.50.75.21:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 1ms, Maximum = 1ms, Average = 1ms
PS C:\Users\Administrator.TPB1> ping 192.168.10.3

Pinging 192.168.10.3 with 32 bytes of data:
Reply from 192.168.10.1: Destination host unreachable.
Request timed out.
Request timed out.
Request timed out.

Ping statistics for 192.168.10.3:
    Packets: Sent = 4, Received = 1, Lost = 3 (75% loss),
PS C:\Users\Administrator.TPB1>

The ping to the 192.168.10.3 gets the Destination host unreachable. Below is the ipconfig for the perimiter VM:

PS C:\Users\Administrator.Administrator> ipconfig /all

Windows IP Configuration

   Host Name . . . . . . . . . . . . : app-exp1-02
   Primary Dns Suffix  . . . . . . . : 
   Node Type . . . . . . . . . . . . : Unkown
   IP Routing Enabled. . . . . . . . : No
   WINS Proxy Enabled. . . . . . . . : No

Ethernet adapter Local Area Connection:

   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : Microsoft Virtual Machine Bus Network Adapter
   Physical Address. . . . . . . . . : 00-15-5D-01-06-08
   DHCP Enabled. . . . . . . . . . . : No
   IPv4 Address. . . . . . . . . . . : 192.168.10.3
   Subnet Mask . . . . . . . . . . . : 255.255.255.0
   Default Gateway . . . . . . . . . : 192.168.10.1
   DNS Servers . . . . . . . . . . . : 201.6.2.163
                                               201.6.2.43

Trying to ping 192.168.10.1 ( the gateway ) from the DMZ machine also does not work. When I use Log & Reports to monitor packets from Wireless network and Perimiter network, I don't get any packets link PING or HTTP that I try to send. But I do get a lot of spoofing messages for NETBIOS broadcasts... it's like Forefront thinks it's coming from a different network, but I don't know why. Please Help!

Tks