The ttl value of ping briefly determines the operating system categories.

You can often roughly judge the type of some operating systems through the ttl value of ping. Here is a summary as follows

1. UNIX and UNIX-like operating systems ICMP echo The TTL field value of the response is 255

2. Compaq Tru64 5.0 The TTL field value of the ICMP echo response is 64

3. Microsoft Windows NT/2K operation The TTL field value of the system ICMP echo response is 128

4. The TTL field value of the Microsoft Windows 95 operating system ICMP echo response is 32

   Of course these ttl values ​​are okay Changes can be made in Windows series systems by modifying the following key values ​​in the registry:
   [HKEY_LOCAL_MACHINE＼sys tem＼CurrentControlSet＼Services＼Tcpip＼Parameters]
   "DefaultTTL"=dword:000000ff
   255--- FF
   128---80
   64----40
   32----20

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