tested on: CentOS Linux 7 with Kernel: 3.10.0-957 with cifs-utils.x86_64 version: 6.2-10.el7
when you ping the host (in this case a QNAP NAS) you – as the administrator – quickly realize – the host is up.
but samba client (cifs from package cifs-utils) falsely reports “host is down” because “host” in this case an QNAP NAS with old firmware does not speak the newer and secure dialects SMB v2.0 and SMB v3.0 and because of insecurity in SMB v1.0 an updated linux distribution will report this error – because cifs-utils per default tries to establish a SMB v2.0 connection – with a server that only speaks SMB v1.0.
instead of issuing a “security warning SMB v1.0 is insecure since ethernal blue exploit” it just fails with the mount error 112: host is down.
host is up.
update all your smb servers so they can speak the more secure dialects SMB v2.0 and SMB v3.0.
“The current support for CIFS, SMB2, SMB2.1 and SMB3 dialects are stable and tested, and use of either CIFS or SMB3 (vers=1 or vers=3.0 on mount) is recommended depending on security requirements (SMB3 is much stronger security), server type and workload.” (src: wiki.samba.org)
all you have to do is “force” cifs-utils to moint with the old insecure protocol by adding the option:
-o vers=1.0 # examples: mount -t cifs //FILE-SERVER-IP-ADDRESS/NAME_OF_SHARE /mnt/cifs --verbose -o user=nobody -o vers=1.0; # mount windows share, you will be asked for password mount -t cifs //FILE-SERVER-IP-ADDRESS/NAME_OF_SHARE /mnt/cifs --verbose -o user=nobody,password=secret -o vers=1.0; # you won't be bothered entering a password # another elaborate example: sudo mount -t cifs -o username=otto,password=geheim,uid=1000,gid=1000,file_mode=0660,dir_mode=0770 -o vers=1.0 //192.168.1.100/Tausch /media/austausch
first of all, THANKS to the work of the cifs-utils team (there is NOBODY FROM MICROSOFT ON THE TEAM!? WHY NOT? Microsoft, if you truly care about OpenSource and Linux you should donate at least one guy that helps implement your (ever changing definition) of this file sharing protocol), but please come up with an less misleading error message for this use-case in the future.
you find the source code of this magnificent piece of open source here: https://git.samba.org/?p=cifs-utils.git;a=summary
“Since 1992, Samba has provided secure, stable and fast file and print services for all clients using the SMB/CIFS protocol, such as all versions of DOS and Windows, OS/2, Linux and many others.” (src)
# get info about installed package yum info cifs-utils.x86_64 Installed Packages Name : cifs-utils Arch : x86_64 Version : 6.2 Release : 10.el7 Size : 175 k Repo : installed From repo : base Summary : Utilities for mounting and managing CIFS mounts URL : http://linux-cifs.samba.org/cifs-utils/ License : GPLv3 Description : The SMB/CIFS protocol is a standard file sharing protocol widely deployed : on Microsoft Windows machines. This package contains tools for mounting : shares on Linux using the SMB/CIFS protocol. The tools in this package : work in conjunction with support in the kernel to allow one to mount a : SMB/CIFS share onto a client and use it as if it were a standard Linux : file system.