Comment 16 for bug 1686099

MichaelB (mrbou) wrote :

I have 5 desktop on Ubuntu 16.04 with various official kernel 4.4, 4.8, 4.10. All this desktop are connected via CIFS to a Windows Server 2008 R2 for a simple shared folder.

After some minutes of activity i got a high CIFS flood traffic between desktop and server. Many giga per desktop are transferred!

CMD (on desktop): sudo tcpdump -p -s 0 port 445

EXAMPLE (This 5 lines below are in loop and repeated all the time):

12:10:14.778859 IP oracle.microsoft-ds > res3-ubuntu.35514: Flags [R.], seq 1, ack 43, win 0, length 0
12:10:14.778891 IP res3-ubuntu.35516 > oracle.microsoft-ds: Flags [S], seq 2388943218, win 29200, options [mss 1460,sackOK,TS val 11568532 ecr 0,nop,wscale 7], length 0
12:10:14.779104 IP oracle.microsoft-ds > res3-ubuntu.35516: Flags [S.], seq 1906593829, ack 2388943219, win 8192, options [mss 1460,nop,wscale 8,sackOK,TS val 172827841 ecr 11568532], length 0
12:10:14.779118 IP res3-ubuntu.35516 > oracle.microsoft-ds: Flags [.], ack 1, win 229, options [nop,nop,TS val 11568532 ecr 172827841], length 0
12:10:14.779210 IP res3-ubuntu.35516 > oracle.microsoft-ds: Flags [P.], seq 1:43, ack 1, win 229, options [nop,nop,TS val 11568532 ecr 172827841], length 42 SMB PACKET: SMBecho (REQUEST)