Created attachment 13451 [details] Logs and tcpdump trace files We are experiencing problems with mounting a DFS share with smb protocol version 2.0 and above on a Windows Server 2008 R2. We have tested the DFS connection on a Ubuntu 16.04.3 system with kernel 4.12.5 from mainline ppa. The command for testing was: mount -v -t cifs //office.babiel.com/Organisation /mnt/dfs -o username=<username>,domain=OFFICE,vers=2.0 mount -v -t cifs //office.babiel.com/Organisation /mnt/dfs -o username=<username>,domain=OFFICE,vers=2.1 Please find the logs and traces from these commands attached: echo 'module cifs +p' > /sys/kernel/debug/dynamic_debug/control echo 'file fs/cifs/* +p' > /sys/kernel/debug/dynamic_debug/control echo 1 > /proc/fs/cifs/cifsFYI echo 1 > /sys/module/dns_resolver/parameters/debug dmesg --clear tcpdump -w ${testcase}.pcap & pid=$! sleep 3 mount.cifs .... (see above) sleep 3 kill $pid dmesg > ${testcase}.log Best regards, Christian Garling
Finally taking a look at this. This seems to also be a problem of cifs.ko failing the initial tree connect and not using the IPC tcon for dfs at the right time. This is a dupe of #12917
*** This bug has been marked as a duplicate of bug 12917 ***