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if I'm currently on Server1 (A windows 2008 server), and I try to access


how is that request handled? Does it stay local to the server entirely (no network access)? Does it go through the loopback? Does it go out to the network the come back, or does it do something else entirely?

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up vote 2 down vote accepted

I believe it uses the loopback adapter.

To test my theory, here's what I did:

  1. Set up a mapped drive that points to the local server (net use Z: \\myfqdn\share\)
  2. Run Sysinternals Procmon to monitor file and network traffic
  3. Duplicate a large file on the mapped drive

The network activity in Procmon showed a large number of packets going between port 445 (SMB) and 57919 (random source port) and both endpoints appear as ::1, the IPv6 loopback address. The task manager shows no network traffic at all, so it's not actually crossing the adapter.

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Seems an accurate test to me. Thanks. – Brian M. Mar 7 '12 at 15:36

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