The optional instructions below are suggestions for the system administrators of a live Submitty installation.

Customize upload students script

The system admin or instructor can upload student data from either an XLSX or CSV spreadsheet of their student classlist (obtained from the university registrar).

sudo ./bin/setcsvfields W X Y Z

Since the format of this data may vary between universities, this command allows customization of what columns from the spreadsheet represent students first name (W), last name (X), campus e-mail (Y), and registration Section ID (Z).

For example: If the students’ first name is column 13, last name is column 12, e-mail is column 15, and section ID is column 7, then the command is:

sudo ./bin/setcsvfields 13 12 15 7

Schedule backups of production server data

Specifically, the configuration, submission, and results data for all courses:


And the central location of the student VCS (git/svn/etc. version control) repositories (if used):


You may want to back up more of /var/local/submitty to save configurations and logs, but be sure to exclude /var/local/submitty/to_be_graded_batch and to_be_graded_interactive

Capture cron error messages

The submitty_daemon user runs the bin/ script. STDERR output from this script should be logged or emailed to ensure that system errors can be reported and addressed.

See cron job details in

Configure log rotation

The defaults will work, but you may want to keep records around for longer and enable compression so that the logs don’t take up as much space. Edit /etc/logrotate.conf and change the log rotation, retention, and compression settings to suit your situation. The comments in the file will tell you what each setting is for, or see logrotate(8) for more details.

Set password policy

It is a good idea to enforce strong passwords and password aging Edit /etc/login.defs to set default password and account expiration and set the umask to block world readable/writable files by default (search for the keywords and update the values after them)


PASS_WARN_AGE   30    

Apply settings by running:


Accept the defaults from the above command.

Edit /etc/pam.d/common-password to tweak settings under the line:

# here are the per-package modules (the "Primary" block)

along the lines of:

password  requisite min=disabled,disabled,15,12,12 similar=deny enforce=everyone retry=3    

Note: The values after min= correspond to password length minimum if they contain: a single character class, 2 classes, a passphrase, 3 classes, 4 classes.

Note: If you would like to allow local machine passwords for pam authentication, make sure the submitty_cgi user is in the shadow group.

Secure SSH

We encourage you to edit /etc/ssh/sshd_config to use only stronger encryption sets along the lines of:

Protocol 2
MACs hmac-sha1,,hmac-ripemd160
Ciphers aes256-ctr,aes192-ctr,aes128-ctr,arcfour256,arcfour128

Block some brute-force ssh connections by typing the following at a command prompt:

sudo bash
iptables -I INPUT -p tcp --dport 22 -m state --state NEW -m recent --set
iptables -A INPUT -p tcp --dport 22 -m state --state NEW -m recent --update --seconds 60 --hitcount 8 -j DROP
iptables-save > /root/eth0.fw

Edit /etc/rc.local to automatically reload the software firewall on boot and add the following just before the exit 0

/sbin/iptables-restore < /root/eth0.fw

Note: This method may not be appropriate or may need to be tuned if you normally expect a lot of ssh connections from a given host. You may also opt to whitelist addresses or networks that are allowed to connect more frequently.

Disable PHP Functions

To improve the security of the system, it might be useful to disable various unused PHP functions. This can be done by modifying the disabled_functions directive. Provided below is the setting used within our Vagrant and live setup:

disable_functions = popen,pclose,proc_open,chmod,php_real_logo_guid,php_egg_logo_guid,php_ini_scanned_files,php_ini_loaded_file,readlink,symlink,link,set_file_buffer,proc_close,proc_terminate,proc_get_status,proc_nice,getmyuid,getmygid,getmyinode,putenv,get_current_user,magic_quotes_runtime,set_magic_quotes_runtime,import_request_variables,ini_alter,stream_socket_client,stream_socket_server,stream_socket_accept,stream_socket_pair,stream_get_transports,stream_wrapper_restore,mb_send_mail,openlog,syslog,closelog,pfsockopen,posix_kill,apache_child_terminate,apache_get_modules,apache_get_version,apache_lookup_uri,apache_reset_timeout,apache_response_headers,virtual,system,phpinfo,exec,shell_exec,passthru,pcntl_alarm,pcntl_fork,pcntl_waitpid,pcntl_wait,pcntl_wifexited,pcntl_wifstopped,pcntl_wifsignaled,pcntl_wexitstatus,pcntl_wtermsig,pcntl_wstopsig,pcntl_signal,pcntl_signal_dispatch,pcntl_get_last_error,pcntl_strerror,pcntl_sigprocmask,pcntl_sigwaitinfo,pcntl_sigtimedwait,pcntl_exec,pcntl_getpriority,pcntl_setpriority,

However, this should be only applied to the php.ini running the web server and not applied to the cgi/php.ini which does require some of these functions to function properly.

Allowing Large Student File Upload Submissions

By default, Apache / Ubuntu limits the size of file upload by POST to 10MB. To increase this edit:


Note: Ubuntu 18.04 is using 7.2, but older versions might be using php7.0-fpm.

Change these variables as appropriate:


And restart apache:

sudo systemctl restart apache2.service
sudo systemctl restart php7.2-fpm.service


sudo service apache2 restart
sudo service php7.2-fpm restart

Note: Ubuntu 18.04 is using 7.2, but older versions might be using php7.0-fpm.

By default, a Submitty electronic gradeable allows students to upload files totaling 100KB. Instructors can adjust this limit per gradeable in the config.json, for example:

// 1 mb maximum submission size
"max_submission_size" : 1000000

If you are having difficulty with student upload size, you can modify the following in /etc/php/7.2/fpm/php.ini:


Just be aware that modifying this number can have repercussions when multiple students are using the system at once.

Show system message to all users

Submitty allows showing a message to all users on all pages. This is useful for advertising events that affect all users, such as system maintainence windows where it would be unavailable. This message is shown in a yellow bar displayed underneath the header.

To add or remove this message, edit /usr/local/submitty/config/submitty.json and add/remove the key/value for system_message. If the key exists, but is empty, no message will be shown.