burble.dn42 provides shell accounts on the following servers:
There is also an anycast address shell.burble.dn42 that will route to the closest server.
The shell service imports user information from the dn42 registry allowing any MNTNER to log in to the servers. Usernames are constructed by lowercasing and removing the ‘-MNT’ suffix.
If you have an
auth attribute with an SSH public key, this will be
imported from the registry and you can use the SSH key to log in to the
MNTNERs without an SSH key must first use the burble.dn42 service portal to set an account password.
For mntner FOO-MNT
Log in to the closest server using your ssh key or burble.dn42 password:
or log in to a specific server:
Your home directory is created automatically on first access and will then
persist across logins.
Home directories are not replicated across servers.
A broad set of command line tools, applications and games are available; the aim is to provide a comprehensive environment that is useful and fun to tinker with.
The current set of packages can be found in the shell config repo:
Requests for additional packages are welcome, please raise these as issues in the repo.
The shell servers include a webserver with user directories (
and CGI (
~/public_html/cgi-bin/) enabled. The webserver is accessed over https
and has a dn42 certificate.
Remember that any files need to be accessible by the webserver which runs as user/group www-data/www-data; CGI scripts must also be executable. The default umask of 077 means that the webserver won’t be able to read your public_html folder or any files within it without changing permissions.
A simplistic approach would be to make your home directory, and public_html directory world readable:
chmod a+x ~ chmod -R a+rX ~/public_html chmod -R a+rx ~/public_html/cgi-bin
A more secure way of allowing access would be to use posix ACLs:
setfacl -m "u:www-data:x" ~ setfacl -Rdm "u:www-data:rX" ~/public_html setfacl -Rdm "u:www-data:rx" ~/public_html/cgi-bin
Note also that home directories are not replicated across each shell server.
If you want to provide services using the anycast address you must copy your code between servers yourself.
You can change your login shell using the burble.dn42 service portal.
The shells have a number of classic text games installed:
Colossal Cave Adventure
Get lost in a twisty little maze of passages
The original time sink
Zork 1, 2 and 3 are available in /usr/local/frotz/
$ frotz /usr/local/frotz/ZORK1.DAT
$ frotz /usr/local/frotz/ZORK2.DAT
$ frotz /usr/local/frotz/ZORK3.DAT
Take a look in /usr/games for more text games.
Cron and other batch or long running tasks are ok, but be a nice neighbour and prioritise other users' interactive use.
Schedule crons to run at random or obscure times to avoid stampeding herds and control your resource usage using tools like nice and ionice.
Clearnet access is provided. Rate limiting allows for a small amount of burst traffic, but then bandwidth is quickly limited to 10mbit/sec. In general, you should be better off using your own clearnet access for large downloads.
SSH forwarding is enabled on the servers.
For example, this means you are able to use the shell servers as a resilient, anycast jump host:
ssh -J shell.burble.dn42 my.other.host.dn42
There are also a small number of X11 apps installed on the servers:
ssh -X shell.burble.dn42 -f 'xterm & xeyes'
The shell servers are monitored using netdata and prometheus, with performance graphs available in grafana.
The netdata dashboard is also directly accessible:
In general, as long as you are not risking the service or other users you should be ok. These services are provided free for your benefit, and the objective is to provide a fun, open environment for dn42 users. Please be considerate in your usage and remember that abusing the service just spoils it for everyone else.
See also the main Abuse Policy.
Configuration for the shell servers is maintained in a git repo:
The repository may be used for raising issues or requesting additional software to be installed.