# Sshfs

You can use sshfs to mount a remote system - accessible via SSH - to a local folder, so you will be able to do any operation on the mounted files with any tool (copy, rename, edit with vim, etc.). Using sshfs instead of shfs is generally preferred as a new version of shfs hasn't been released since 2004.

## Installation

Install sshfs from official repositories. This should install fuse and sshfs, and maybe other packages.

## Usage

First a kernel module should be loaded, so as root, do:

    # modprobe fuse

Note: This will be done automatically when you run the sshfs command, so there's no need to add a modprobe conf file to make it load at boot. If you get an error message about needing to load the module when you run sshfs, you probably didn't reboot after a kernel update.

Check if fuse is active:

    systemctl list-units --all|grep fuse

     sys-module-fuse.device    loaded active   plugged       /sys/module/fuse

Note: You may have to execute the sshfs command first, before systemctl will show that fuse is active. Systemd will activate the fuse device once a program is run that requires it.

### Mounting

You will use the command `sshfs`. To mount a remote directory:

    $ sshfs USERNAME@HOSTNAME_OR_IP:/PATH LOCAL_MOUNT_POINT SSH_OPTIONS

For example:

    $ sshfs sessy@mycomputer:/home/sessy /mnt/sessy -C -p 9876

Where `9876` is the port number.

Also, make certain that before connecting, you set the file permissions for any local client folders you will attempt to mount a remote directory to. I.e., do not have everything owned by root! You could also run the mount command as a regular user, it should work as well.

SSH will ask for the password, if needed. If you do not want to type in your password 49 times a day, then read this: How to Use RSA Key Authentication with SSH or Using SSH Keys.

Tip: To quickly mount a remote dir, do some file-management and unmount it, put this in a script:

    sshfs USERNAME@HOSTNAME_OR_IP:/PATH LOCAL_MOUNT_POINT SSH_OPTIONS
    mc ~ LOCAL_MOUNT_POINT
    fusermount -u LOCAL_MOUNT_POINT

This will mount the remote directory, launch MC, and unmount it when you exit.

### Unmounting

To unmount the remote system:

    $ fusermount -u LOCAL_MOUNT_POINT

Example:

    $ fusermount -u /mnt/sessy

## Chrooting

You may want to jail a (specific) user to a directory.To do this, edit `/etc/ssh/sshd_config`:

    /etc/ssh/sshd_config

    .....
    Match User someuser
           ChrootDirectory /chroot/%u
           ForceCommand internal-sftp #to restrict the user to sftp only
           AllowTcpForwarding no
           X11Forwarding no
    .....

Note: The chroot directory must be owned by root, otherwise you will not be able to connect. For more info check the manpages for `Match, ChrootDirectory` and `ForceCommand`.

## Helpers

If you often need to mount sshfs filesystems you may be interested in using an sshfs helper, such as sftpman.

It provides a command-line and a GTK frontend, to make mounting and unmounting a simple one click/command process.

## Automounting

Automounting can happen on boot, or on demand (when accessing the directory). For both, the setup happens in `/etc/fstab`.

Note: Be mindful that automounting is done through the root user, therefore you cannot use Hosts configured in `.ssh/config` of your normal user.

To let root user use an SSH key of a normal user, specify its full path in option `IdentityFile`.

And most importantly, use each sshfs mount at least once manually while root so the host's signature is added to the `.ssh/known_hosts` file.

### On demand

With systemd on-demand mounting is possible using `/etc/fstab` entries.

Example:

    user@host:/remote/folder /mount/point  fuse.sshfs noauto,x-systemd.automount,_netdev,users,idmap=user,IdentityFile=/home/user/.ssh/id_rsa,allow_other,reconnect 0 0

The important mount options here are noauto,x-systemd.automount,_netdev.

- noauto tells it not to mount at boot
- x-systemd.automount does the on-demand magic
- _netdev tells it that it's a network device, not a block device (without it "No such device" errors might happen)

### On boot

An example on how to use sshfs to mount a remote filesystem through `/etc/fstab`

    USERNAME@HOSTNAME_OR_IP:/REMOTE/DIRECTORY  /LOCAL/MOUNTPOINT  fuse.sshfs  defaults,_netdev  0  0

Take for example the fstab line

    llib@192.168.1.200:/home/llib/FAH  /media/FAH2  fuse.sshfs  defaults,_netdev  0  0

The above will work automatically if you are using an SSH key for the user. See Using SSH Keys.

If you want to use sshfs with multiple users:

    user@domain.org:/home/user  /media/user   fuse.sshfs    defaults,allow_other,_netdev    0  0

Again, it's important to set the _netdev mount option to make sure the network is available before trying to mount.

### Secure user access

When automounting via `/etc/fstab`, the filesystem will generally be mounted by root. By default, this produces undesireable results if you wish access as an ordinary user and limit access to other users.

An example mountpoint configuration:

    USERNAME@HOSTNAME_OR_IP:/REMOTE/DIRECTORY  /LOCAL/MOUNTPOINT  fuse.sshfs noauto,x-systemd.automount,_netdev,user,idmap=user,transform_symlinks,identityfile=/home/USERNAME/.ssh/id_rsa,allow_other,default_permissions,uid=USER_ID_N,gid=USER_GID_N 0 0

Summary of the relevant options:

- allow_other - Allow other users than the mounter (i.e. root) to access the share.
- default_permissions - Allow kernel to check permissions, i.e. use the actual permissions on the remote filesystem. This allows prohibiting access to everybody otherwise granted by allow_other.
- uid, gid - set reported ownership of files to given values; uid is the numeric user ID of your user, gid is the numeric group ID of your user.

## Options

sshfs can automatically convert your local and remote user IDs.

Add the idmap option with user value to translate UID of connecting user:

    # sshfs -o idmap=user sessy@mycomputer:/home/sessy /mnt/sessy -C -p 9876

If you have a different login on the remote system, it can still work if you provide the ssh standard option User:

    # sshfs -o idmap=user,User=sessy2 sessy@mycomputer:/home/sessy /mnt/sessy -C -p 9876

(I've used first form, second is based on docs, so YMMV, but it should at least be close)

## Troubleshooting

### Checklist

Read the SSH Checklist Wiki entry first. Further issues to check are:

1. Is your SSH login sending additional information from server's `/etc/issue` file e.g.? This might confuse SSHFS. You should temporarily deactivate server's `/etc/issue` file:

    $ mv /etc/issue /etc/issue.orig

2. Keep in mind that most SSH related troubleshooting articles you will find on the web are not Systemd related. Often `/etc/fstab` definitions wrongly begin with `sshfs#user@host:/mnt/server/folder ... fuse ...` of using the syntax `user@host:/mnt/server/folder ... fuse.sshfs ... x-systemd, ...`.

3. Check that the owner of server's source folder and content owned by the server's user.

    $ chown -R USER_S: /mnt/servers/folder

4. The server's user ID can be different from the client's one. Obviously both user names have to be the same. You just have to care for the client's user IDs. SSHFS will translate the UID for you with the following mount options:

    uid=USER_C_ID,gid=GROUP_C_ID

5. Check that the client's target mount point (folder) is owned by the client user. This folder should have the same user ID as defined in SSHFS's mount options.

    $ chown -R USER_C: /mnt/client/folder

6. Check that the client's mount point (folder) is empty. By default you can't mount SSHFS folders to non-empty folders.

7. If you want to automount SSH shares by using an SSH public key authentication (no password) via `/etc/fstab`, you can use this line as an example:

    USER_S@SERVER:/mnt/on/server      /nmt/on/client        fuse.sshfs      x-systemd.automount,_netdev,user,idmap=user,transform_symlinks,identityfile=/home/USER_C/.ssh/id_rsa,allow_other,default_permissions,uid=USER_C_ID,gid=GROUP_C_ID,umask=0   0 0

Considering the following example settings ...

SERVER = Server host name (serv) USER_S = Server user name (pete) USER_C = Client user name (pete) USER_S_ID = Server user ID (1004) USER_C_ID = Client user ID (1000) GROUP_C_ID = Client user's group ID (100)

you get the client user's ID and group ID with

    $ id USERNAME

this is the final SSHFS mount row in `/etc/fstab`;

    pete@serv:/mnt/on/server      /nmt/on/client        fuse.sshfs      x-systemd.automount,_netdev,user,idmap=user,transform_symlinks,identityfile=/home/pete/.ssh/id_rsa,allow_other,default_permissions,uid=1004,gid=1000,umask=0   0 0

8. If you know another issue for this checklist please add it the list above.

### Connection reset by peer

- If you are trying to access the remote system with a hostname, try using its IP address, as it can be a domain name solving issue. Make sure you edit `/etc/hosts` with the server details.
- If you are using non-default key names and are passing it as `-i .ssh/my_key`, this won't work. You have to use `-o IdentityFile=/home/user/.ssh/my_key`, with the full path to the key.
- Adding the option '`sshfs_debug`' (as in '`sshfs -o sshfs_debug user@server ...`') can help in resolving the issue.
- If you're trying to sshfs into a router running DD-WRT or the like, there is a solution here. (note that the -osftp_server=/opt/libexec/sftp-server option can be used to the sshfs command in stead of patching dropbear)
- Forum thread: sshfs: Connection reset by peer

Note: When providing more than one option for sshfs, they must be comma separated. Like so: '`sshfs -o sshfs_debug,IdentityFile=</path/to/key> user@server ...`')

### Remote host has disconnected

- If you recieve this message directly after attempting to use sshfs, try checking the path of your Subsystem listed in /etc/ssh/sshd_config on the remote machine to see if it is valid.

Note: The default value for Subsystem should be `Subsystem sftp /usr/lib/ssh/sftp-server`

- You can check this by typing `find / grep XXXX` where XXXX is the path of the subsystem

### Thunar has issues with FAM and remote file access

If you experience remote folders not displaying, getting kicked back to the home directory, or other remote file access issues through Thunar, replace fam with gamin. Gamin is derived from fam.

### Shutdown hangs when sshfs is mounted

Systemd may hang on shutdown if an sshfs mount was mounted manually and not unmounted before shutdown. To solve this problem, create this file (as root):

    /etc/systemd/system/killsshfs.service

    [Unit]
    After=network.target

    [Service]
    RemainAfterExit=yes
    ExecStart=-/bin/true
    ExecStop=-/usr/bin/pkill sshfs

    [Install]
    WantedBy=multi-user.target

Then enable the service: `systemctl enable killsshfs.service`

## See also

- sftpman - sshfs helper tool
- SSH
- How to mount chrooted SSH filesystem, with special care with owners and permissions questions.

Category:

- Secure Shell