Maybe it is a amateur question but here it goes: At the university we have a folder /vol. This folder is absolutely empty until you "cd" into a directory which exist there. E.g. "cd /vol/directoryWhichExists". Then this directory is mounted and accessible.

My questions are:

  • Why should an Admin do it that way? (sequrity, clean overview, network volumes, ???)

  • If there is a security reason, why not bruteforcing every possible directory?

  • Is there a possibility to list all directories in that folder?

Greets tiko

2 Answers 2


This configuration is called automount or autofs and mostly the configuration can be found in /etc/auto.master

For your questions:

  1. just clean overview an minimizing network traffic for network volumes (but this is minimal if a volume is not accessed)
  2. i can't imagine any security reasons
  3. a cd /vol; ls -R should do (Parameter -R for recursive listing), normally a ls -R /vol should do it but this depends on the configuration of autofs

Forgot to metion that we got a lot of problems with autofs in our 500 virtual machines production environment so we moved back to static configuration in /etc/fstab.


There are 3 main reasons for using automounters and/or dynamic fuse filesystems

  • Huge amount of data, keep things clean When you have many data, spread all over the place, you may not want to have all those mount points always active, the df would be full of entries, people enter on the wrong directories, too much information confuse people

  • dynamic content Backups, remove machines and other dynamic content that changes over time and only is enabled when someone access to it. One of the main examples is the sshfs of smbnetfs, were the directory names is the hostname (and share) and fuse will connect to the remote server and show the remote content as a normal local filesystem

  • avoid lockups NFS and other network file systems may lockup on network problems or even just network latency. Having a directory with many nfs would increase this problem and block a user on a nfs that he didn't need

As for security reasons i can only see security by obscurity, because the filesystem permissions would take care of the real security... but some people like it anyway.

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