Mount CIFS Host is down

Solution 1:

This could also be because of a protocol mismatch. In 2017 Microsoft patched Windows Servers and advised to disable the SMB1 protocol.

From now on, mount.cifs might have problems with the protocol negotiation.

The error displayed is "Host is down.", but when you do debug with:

smbclient -L <server_ip> -U <username> -d 256

you will get the error:

protocol negotiation failed: NT_STATUS_CONNECTION_RESET

To overcome this use mount or smbclient with a protocol specified.

for smbclient: add -m SMB2 (or SMB3 for the newer version of the protocol)

smbclient -L <server_ip> -U <username> -m SMB2

or for mount: add vers=2.0 (or vers=3.0 if you want to use version 3 of the protocol)

mount -t cifs //<server_ip>/<share> /mnt/<mountpoint> -o vers=2.0

Solution 2:

On archlinux after a recent package update, I had to add vers=1.0 to my mount options. I'm connecting to an old centos 5 box and up until yesterday I could connect without explicitly stating a version number.

CIFS in linux kernel 4.13 now defaults to SMB 3.0 and in kernel 4.14 it tries 2.1 and higher. See this change log.

Solution 3:

USB-stick at Fritz NAS showed "Host Down" for Ubuntu 17.10:

Defining the version (vers=1.0) worked - here's the full string:

sudo mount -t cifs -o vers=1.0,_netdev,username=<user>,password=<pwd>,uid=1000,gid=1000  //192.168.178.1/fritz.nas <local mountpoint>

Solution 4:

Similar problem after upgrade to ubuntu 17.10, with an old Buffalo Diskstation. Solved by adding in /etc/fstab the "vers=1.0" option:

//myWDhostname/partage /media/Partage cifs guest,vers=1.0 0 0

Solution 5:

Sorry if this is a late response (I realise it's an old thread), however I have just discovered there is another possible reason why mount.cifs would say the host is down.

I have an antivirus with a firewall and even though I set it explicitly to allow "windows file and print sharing" -- a predefined rule, it was still blocking connections. I had that proven by disabling the firewall temporarily. Hope this helps someone, host is down might not mean it's not responding to pings, but could mean it's not responding to authentication attempts.