It seems that SMB2 and SMB3 has been disabled in Raspberry Pi kernel (at least). Would it be possible to re-enable them ?
Here is what I re-enabled:
index 4f379ef..c05a086 100644
@@ -1,6 +1,6 @@
--- /dev/null 2016-02-29 09:14:50.439999999 +0000
+++ b/.config 2016-03-01 12:19:28.490204084 +0000
-@@ -0,0 +1,4877 @@
+@@ -0,0 +1,4878 @@
+# Automatically generated file; DO NOT EDIT.
+# Linux/arm 4.4.3 Kernel Configuration
@@ -4381,8 +4381,9 @@
+# CONFIG_CIFS_ACL is not set
+# CONFIG_CIFS_DEBUG2 is not set
-+# CONFIG_CIFS_DFS_UPCALL is not set
-+# CONFIG_CIFS_SMB2 is not set
+# CONFIG_CIFS_FSCACHE is not set
+# CONFIG_NCP_FS is not set
+# CONFIG_CODA_FS is not set
SMB1 is disabled on my Windows Server 2012 DC and I'm not able to connect any of my cifs share without them. I recompiled the kernel with these options and I'm able to connect by adding vers=3.0 to mount command.