I frequently VPN to different networks to assist our clients. I've noticed
that I lose the ability to connect to shares on servers on my LAN when I
have a VPN session up. I can still PING local devices, but it seems that my
Windows credentials change to match that used for the VPN. (I can look at
the event log entries on a LAN server and see that there are attempts to
connect using the domain/user credentials for the VPN I've connected to.)

Even network shares that I've established prior to connecting the VPN
session will fail (presumably after some timeout that requires the
credentials to be refreshed).

This behavior is obviously different from all prior versions of Windows and
makes my job significantly more difficult.

Does anyone have information on why this change was made, and, more
importantly, if there's any way around it?

Thanks

LAN access on a VPN tunnel is mandated through network lists which are comprised of allowed subnets or ip ranges within the network subnet.

Examples would include:

172.0.0.0 255.0.0.0
10.0.1.0 255.255.255.0

It sounds as if your subnets are allowed (pings work) but your AAA is not. Unless you are authenticating on the VPN using your normal, domain credentials, which I assume have the appropriate share rights, you'll probably have to setup a new mapped drive which uses the aforementioned authentication credentials. (see 'connect using' when setting up the mapped drive to the network share.) Otherwise, determine if the VPN comes from a different domain/DMZ and grant share rights to that account/domain.

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