ICT services

ISSC services

This page attempts to describe the current LIACS ICT landscape, which is part of Leiden University's ICT infrastructure as provided by the ISSC.

Research and Education Laboratory (REL) and sublabs

Note that in addition to and separate from the above, LIACS also has its own Research and Education Laboratory (REL) (link only internally accessible) which provides additional services for LIACS staff and students. 
This lab includes, amongst other things, the high performance computing servers DAS-5, the Little Green Machine (LGM), and the Data Science lab (link only internally accessible). 


All general ICT support is provided by the ICT Shared Service Center (ISSC).

Generally, you will need your ULCN username so that the helpdesk can identify you.
Sometimes, it helps to mention that you work (or are are student) at LIACS so that the appropriate responsible employee within the ISSC can be found more quickly.
If you know the name of the ISSC employee likely responsible for handling your request, you can mention this name in your call to speed up the process.
For an issue which is not directly resolved after calling, insist on a helpdesk issued support ticket ID to reference your issue in the future.

If for some reason your support call is not handled adequately or quickly enough by the ISSC, then in cooperation with the LIACS ICT Coordinator (institute manager) issues can be escalated to Hans van Eck, the ISSC service manager for LIACS.

Accounting & Access

All current students and staff have an ULCN account which provides access to most university services. You obtain this account upon registration as a student or upon employment as staff. The username looks like s[studentnumber] for students and [lastname][initials][prefixes] for staff. The password is sent in a paper letter to your home address.
Lost your ULCN password? If needed, this password can be reset via the ISSC through the Account Services or via the helpdesk phone number.

All LIACS students and staff should have access to all LIACS-specific services such as the webserver, remote server, shared folders, etc.
If this is not the case, for example for exchange students, guests or other "special" cases, then you have to specifically ask the ISSC helpdesk to add the missing ULCN usernames to the LIACS "group", which is maintained within the systems of the ISSC.



Under Windows, shared folders can be obtained for a group of users via the ISSC Helpdesk.
Under Linux, the shared folder for LIACS can be found at
It should be possible to share large files between LIACS staff and students through this folder without  limitations.


All workstations are managed by the ISSC, and all student workstations and scientific staff workstations should have an Intel Core i7 CPU with 16GB RAM and at least 1TB storage.

  • Student workstations with dualboot Ubuntu LTS (Linux) and Windows for all LIACS students are available in Snellius rooms 302/304, 306/308, 411 and 303.
  • Staff workstations are available in three forms:
    • Managed, with dualboot Linux and Windows. 
    • Semi-managed: the same as above, but with administrator/root rights, at the cost of sacrificing helpdesk workstation support other than a re-install. 
    • Self-managed: you can choose to have your fully self managed machine, either within the ISSC domain or directly within the LIACS REL network. No helpdesk workstation support is provided.

      Contact the ICT coordinator (institute manager) to get your choice executed.


You can choose at least three access points for wireless access.

  • Eduroam (works at other universities as well, but requires some setting up)
  • Access point named Leiden University (authenticate in browser via ULCN or a guest code)
  • The LIACS wireless access point wlan 3 which also provides access to the LIACS Research and Education Lab (REL).
    This access point is only available in the Snellius building.
    Password can be obtained by asking a fellow student or staff member.


On all staff and student workstations, Snellius printers should be directly available. If this is not the case for your machine, contact the ISSC Helpdesk.
Printer names correspond to room numbers. Staff can use for example the printers near room 123, 145, and 156 (post room). Students can for example use printers near 302 and 410.

Currently, a CUPS printserver under the name (within LIACS) or (within Leiden University domain) is available through port 631 and has a webinterface at It serves at least all printers in the Snellius building and Campus The Hague.
You can print to this server from within the LIACS domain, so via VPN or WiFi.

  • Under Ubuntu, simply edit /etc/cups/client.conf so that it contains:
    With newer CUPS versions (e.g., in Ubuntu 13.x+), you should use:
  • Under Windows, assuming you are within the LIACS domain (so, on wlan 3 WiFi, logged in via VPN, or on a machine within the REL), printers should be found automatically by the printer adding wizard.


All e-mail services are handled by the ISSC, thus authentication takes place via ULCN.

  • Students have an uMail e-mailaddress which looks like
  • LIACS staff members have an address which looks like
    • is a valid (sometimes convenient) alias for all LIACS staff members. 
    • A webmail Outlook interface is available.
    • Microsoft Exchange mailserver:
    • Incoming mailserver (IMAP): (port: 993, SSL, credentials required)
    • Internal outgoing mailserver (SMTP): (port: 25)
    • External outgoing mailserver (SMTP): (port: 587, credentials and STARTLS required)

If, as a staff member, you want your e-mail forwarded to some other address (for example, your GMail-address), or if you want your e-mail to be forwarded after you leave the institute, then you will have to request this at the ISSC Helpdesk, sometimes in collaboration with the ICT coordinator (institute manager).

Legacy e-mail addresses: all LIACS students and LIACS staff enrolled or employed before 2014 als had an e-mail address. These addresses should all have been forwarded to the new addresses. In case of problems or e-mail addresses that are no longer being properly redirected, the ISSC can fix forwards upon request.


You can send an e-mail to any one of the following mailinglists if you are on this list yourself.

  • - all "LIACS inhabitants" of the Snellius building: payed employees, PhD students and and guests
  • - all LIACS teaching staff
  • - all LIACS PhD studentes with an office in the Snellius building
  • - all LIACS scientific personnel with an office in the Snellius building
  • - all scientific supervising LIACS personnel (group leaders etc.)


All LIACS staff and students should have access to the LIACS-ISSC webserver named
It publishes user websites at
You can connect to it only from within the university domain. It can be accessed via SSH and SFTP. Use your ULCN credentials, and place your website in the public_html folder.

A document on this webserver and the connected MySQL server (for which a PHPMyAdmin is available via has been written by the ISSC.

To provide easy access to your website from your regular Linux workstation in the folder ~/public_html, you can manually mount your public_html folder on the webserver in your regular homedirectory using sshfs, for example as follows on a workstation:
mkdir ~/public_html (once)
sshfs <user><user>/public_html ~/public_html
(each time you want to mount your public_html folder, <user> is your ULCN username)
You can place a script with the above line in your "usr/bin" folder so that you can mount your website with one simple command.

To see PHP errors, you should place a file named .htaccess in your public_html folder containing the text php_flag display_errors on
Then, you should explicitly state on top of your script that you want to see errors, for example using the PHP command error_reporting(E_ALL);

File access is arranged using ACLs (e.g., through setfacl and getfacl). For example, to give the webserver write access to a folder, use:
setfacl -R -m group:www:rwx /path/to/rw/folder
setfacl -R -m default:www:rwx /path/to/rw/folder

sshfs public_html2

Remote access

To access the university environment from another location, use any of the following methods:

  • There is an SSH gateway which can be used to access the ISSC Linux environment.
    The ssh -K option may sometimes help to ensure that your Kerberos authentication works as expected, and homedirectories get mounted properly.
    To use X forwarding, use for example:
    ssh -t -A -X
    The gateway itself only provides access to your homedirectory via ~/homedir/ and blocks all binaries.
    To be able to do work, you should connect further to one of the terminal servers.
    To connect directly (from anywhere) with X forwarding to the terminal server (in this case huisuil01), use for example:
    ssh -t -A -X <user> ssh -X huisuil01
  • The software and environments of the terminal server machines should be identical to regular UNIX workstations. From the gateway or within the university domain you can access these servers by typing:
    This will refer you to either one of the LIACS servers, and (each of them can also be reached separately).
    These machines each have four hyperthreaded quadcore Intel Xeon CPU's, type E5-2667 running at 3.30GHz and 48GB of RAM.
    A document on these servers has been written by the ISSC.
    The ISSC also has general machines and available. 
  • Citrix remote desktop provides a webbased Citrix interface to access some applications in the Windows environmen which can be accessed via
  • The ISSC does not offer VPN access. VPN is however available for LIACS staff and students via the Research and Education Lab, see
  • Remote access to a specific staff Linux and/or Windows machine can be requested at the ISSC helpdesk.


To request additional software on a workstation which cannot be installed locally or without administrator rights, contact the ISSC Helpdesk.
The ISSC provides basic university-wide software for the entire university, and additional software is available for LIACS.

In Windows, it is sometimes necessary to go to Control Panel, Run Advertised Programs to obtain certain specific software on a certain machine.
Under UNIX, some shared software such as Xilinx, R, Eclipse and Matlab is available via /vol/share/software/
There is a '<xy>-README" with instructions on how to use the package. For multiple versions the subfolders are listed per version.

ISSC procedure: If new specific software is needed for the LIACS student workstations, please submit the request on time (1 month in advance). ISSC will contact the lecturer for an intake to discuss specifics. If necessary the software will be purchased (potential expenses need approval of the ICT coordinator (institute manager). After acceptance the lecturer will test the software. When necessary the software will be adjusted before being available for the educational workplaces. The ISSC has a form for a software request.

Managing publications (staff only)

Throughout the year, all LIACS staff members are encouraged to keep their publication lists up to date through CONVERIS (authenticate using ULCN).
A few tips for using Converis:

  • Fill in the "Internal Authors"
  • Fill in "All Authors" in the same layout as the "Internal Authors"
  • Always fill in the "Year"
  • Submit to repository: fill in "No"
  • Always fill in the "Research Area", which you find under "2. Thematic Classification": choose between (1) Algorithms and the Foiundations of Software Technology or (2) Computer Systems, Imagery and Media
  • Validated by WD: "No"

If you keep your list up to date, it will also automatically be updated on the profile pages on the university webpage. Assistance on Converis can be provided by the LIACS secretary.

Last edited on 13 Jan 2019 at 10:06