IP address already assigned to another adapter

This issue occurs if a network adapter with the same IP address is in the Windows registry but is hidden in the Device Manager (My Computer > Properties > Hardware > Device Manager). This hidden adapter is called a ghosted network adapter.

• You may see this if you recently performed a P2V and the resulting virtual machine still has the physical NICs and drivers for those NICs present. These ghost NICs have the old IP address and the virtual NIC cannot be assigned the same IP address.

Using the Show hidden devices option in the Device Manager (View > Show hidden devices) does not always show the old virtual NIC (ghosted adapter) to which that IP Address is assigned.

 

To resolve this issue, make the ghosted network adapter visible in the Device Manager and uninstall the ghosted network adapter from the registry:

1. Click Start > Run.
2. Type cmd and press Enter.
3. At the command prompt, run this command:
   Note: In Windows 2008 and Windows 7, open the command prompt using the Run as Administrator option.
   
   set devmgr_show_nonpresent_devices=1
   Note: If this command does not work (a possibility in Windows Server 2000 and 2003), you may need to add the parameter to Windows and set its value:
   
   
   1. Right-click the My Computer desktop icon and choose Properties.
   2. Click the Advanced tab and select Environment Variables.
   3. In the System variables section, click New.
   4. Set the Variable name to devmgr_show_nonpresent_devices and set the Variable value to 1 to enable the parameter.
   5. Click OK to add the variable to Windows.
      
4. Start the Device Manager by running this command from the same command prompt:
   
   start devmgmt.msc
   
5. Click View > Show Hidden Devices.
6. Expand the Network Adapters tree (click the plus sign next to the Network adapters entry).
7. Right-click the dimmed network adapter, then click Uninstall.
8. Once all of the grayed out NICs are uninstalled, assign the IP address to the virtual NIC.
   
   Note: To assign the IP address to the virtual NIC on the command line, run the command:
   
   netsh interface ip set address "Local Area Connection #" static IP_Address Subnet_Mask Default_Gateway
   
   For example:
   
   netsh interface ip set address "Local Area Connection 2" static 192.168.1.101 255.255.255.0 192.168.1.1
   
   
9. Close the Device Manager

Source of this article: VMware KB1179 

Exchange DAG replication using secondary NIC betwene servers on different subnets

Recently I ran into a problem with Exchange 2010 DAG configuration. I needed to replicate databases between servers that were geographically in different sites and were each on their own separate subnets. For this purpose I wanted to use our secondary data line in order to avoid overloading our main production line with replication traffic. DAG was all set and replicating fine over production line but when I disabled replication on main NIC's and enabled it on secondary NIC's routed via secondary data line, Exchange was still pushing replication via primary NIC. Issue resolved after I collapsed DAG network on secondary ISP into a single DAG network adding both near and far subnet into it. Great article that talks just about that particular setup you can find right here: http://blogs.technet.com/b/timmcmic/archive/2011/09/26/exchange-2010-collapsing-dag-networks.aspx

Cisco VPN isakmp ports

What are the ports to be opened on ASA if I need to VPN from inside my network to another site providing cisco VPN connection?

access-list inbound_traffic_on_inside extended permit udp any any eq isakmp
access-list inbound_traffic_on_inside extended permit esp any any
access-list inbound_traffic_on_inside extended permit udp any any eq 10000