In my company's physical office, there is no domain controller setup, just a bunch of computers ranging from Windows XP to Windows 10 that are all part of the same workgroup in the same LAN. These computers can access shared folders on other computers in the network by logging with user accounts that exist on those computers. With me so far?
Problem: I've set up a VPN through the router (netgear router with openvpn client), and I can see the shared folders on "Most" computers. I'm using Windows XP Professional, and inside the VPN I can access computers that are Windows XP or newer. I'm getting a local IP address from the router's DHCP and all that seems perfect. But I'm having I'm having problems accessing Windows 2000 computers. I try to log in and receive the error "STATUS_LOGON_FAILURE". I'm typing the correct username and password, and just can't figure out why it's not working.
I'm using Wireshark to analyze the packets and can't really see anything in there that is that much different in the SMB communication between these machines, and I'm not really sure where to start. Since XP machines in the same office behind the same router can access Windows 2000 machines, but I can't through the VPN, it seems the problem might have something to do with that. Any tips on how to trouble-shoot this?
Thanks!
I found the solution. It had to do with this registry setting:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa\lmcompatibilitylevel
On all machines in the office, this value was set to 0. If I set mine to 0, I can login fine. Of course, the REAL problem is that 0 seems pretty out-dated and insecure, so now I'll need to review whether all the old machines in the office can support a NTLMv2 so I can update that, but that's a different issue. So this is SOLVED.