The Time To Live (TTL) value in an IPv4 packet determines the maximum number of links or hops on which an IPv4 packet is allowed to travel before being discarded. The default TTL value in Windows Server 2008 and Windows Vista is set to 128. While the defaults are good enough and may never need changing, there may be instances where you may want to change the default TTL.
The following procedure to edit the Windows Registry should help you change the default TTL value of 128.
To modify the default TTL in Windows Server 2008 & Windows Vista,
1. Click Start - Search and type “regedit”. This launches the WIndows Registry.
2. In the registry, navigate to the following registry key
3. In the right pane, right-click and select New – DWORD (32-bit value) and set its name as “DefaultTTL” and set its value anything between “0″ and “255″. The value sets the number of Hops or links the packet traverses before being discarded.