Wanted to share a odd ball issue that started up last week, and attempting to resolve.
Sometime between May 12th - 14th, network changes were made (probably with concerns toward cyber security) that effect SMB.
Starting on the 15th, we started having issues with SMB connections through the OS X GUI. This was specific to printing, and windows file share connections (oddly enough our DFS connections still worked). We have gone through many steps attempt to track this down. Wireshark network sniffing shows SMB2 connections being attempted (and requested) by the fileserver; however, nothing mounts, nor a return from the file server doesn't occur. We are suspicious of software firewalls possibly being put in place that we are not aware of.
With all that being said. I am looking for commands, or plist editing that we might be able to try forcing SMB 2/3 through the GUI server connections (vs. smb1, then handshake and update to SMB2), just to see if this quick fixes the matter.
I believe OS X systems update upward on SMB, not downward (i.e. it will except going to smb2 from smb1 request, but not smb2 to smb1).
We are also investigating ntlm authentication as suspect, but that is another story.
oddly enough through terminal command line YOU CAN mount the fileserver. Which once again boggles our mind why it won't work through GUI.
This is something we have never ran into before.