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FAQ General

This page is a collection of frequently asked questions related to the Nikhef infrastructure.

How should we dispose of hardware supplied by Nikhef CT?

It is mandatory to return all hardware supplied/lent by CT via/through the CT Helpdesk.

This concerns very old, defective, reusable and surplus items.

There are several reasons for this, namely:

1) that no secret, confidential, personal and/or research data/information (documents, data, login details, etc.) leaves Nikhef via hardware or can reach another user/external party,

2) that reusable hardware is first prepared before the next user puts it back into use,

3) that old and defective items are disposed of in a responsible and sustainable manner,

4) and not unimportantly, the returned items are disconnected in our Asset Management System from the location and/or the person they are registered with us.

Disposal/returning is very simple; bring it to the Helpdesk or send an email to with the question whether we would like to collect it. Indicate where exactly it is and which items are concerned.

Can we buy hardware from Nikhef CT?

Due to the renovation and a lot of other activities, no CT hardware sale will be held in the foreseeable future. We hope for your understanding.

For your mobile equipment (phones, laptops) provided by Nikhef that are subject to the "Regulation Mobile Electronic Work Facilities", the options provided in that regulation apply.

How can I add my photo to the Nikhef Intranet Employee Database?

The Nikhef Intranet Employee Database contains entries for all employees with their contact information. The Intranet does not include a photo by default because the European privacy law GDPR (called AVG in Dutch) requires explicit permission to publish photos of individuals.

To have your picture published on the Intranet, the following conditions must be met:

  • You are registered as employee of Nikhef.
  • Your picture has been taken by our photographer.
  • You have given consent to publish your picture.

To give the required consent, open the SSO page in your browser. Under Your profile settings you can grant or withdraw permission to publish your picture by selecting the option "Please do show my picture publicly" or "Do not show my picture publicly", respectively. After changing the value, confirm your changes under Confirmation of changes by entering your password and clicking the button "Change configuration".

Please contact the Secretariat ( to make an appointment to have your picture taken if that has not happened before.

Note: after giving consent, the picture is visible from within Nikhef and from the public internet.

Why is the login server blocking connections?

You are attempting to log in to and instead of a connection you get a "no route to host" error message. Other destinations on the Nikhef network (for example, this page) are reachable for you though.

Cause: What you are experiencing is in all likelihood not a network connectivity issue, but the result of a security system on the server. To prevent flooding with illegitimate login attempts, this server blocks any IP address from which too many failed login attempts have been made.

Every time a user attempts to log in and fails, a flag is raised. If this happens several times in a row, a short-term block will be enforced. If two of those short-term bans get issued in succession, a longer ban is issued. If the same happens even more regularly, the IP address gets banned indefinitely.

How to fix this: In case you are experiencing the symptom described above, please contact our service desk. Explain what your issue is and also provide the IP address you are connecting from when you have this problem. You can find out what your IP address is in various ways. The simplest is to just open the address in your browser.

The Helpdesk will then notify the administrators of the login server who can "unblock" your IP address.

But I did not fail on login!

It is absolutely possible that you did not directly fail to provide a username and password correctly, but you can still generate login failures. This usually happens if you have a piece of software (like and SSH or SFTP/SCP client) that offers to log in automatically as you start it. Check the following:

  • Did you recently change your password?
  • Do you have any applications which automatically connect to
  • Are any programs running in the background that use automatic logins? (On Windows, check the bottom right of your taskbar for that)
  • Are the login credentials still valid (i.e. is the new password entered)?

It is generally advised not to use automatic logins, but if you insist on using them, please make sure you have all passwords updated before starting up the application.

Why am I getting a python segmentation fault?

A python segmentation fault can be caused by many things. Some issues could be:

  1. A mismatch between python versions. Check the version of python with python -V—is your env using a different version than your system? Check for example using which python and readlink -e $(which python). This could be relevant for example when you're using a conda environment or python venv.
  2. Are your locale settings correct (specifically the LC_CTYPE variable)?
    • Check if the LC_CTYPE environment is set with a printenv | grep LC_CTYPE command. If it only returns UTF-8 without a language specification, this is likely causing the segmentation fault.
    • You can try to run an strace on the python command by running strace -f -o [create a name for the file ] python. strace produces A LOT of output. You may want to write this out to a file like in the example above. If it stops at the locale settings with something like 498419 open("/usr/lib/locale/UTF-8/LC_CTYPE", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory).

      If the issue is with the locale settings, try unsetting your LC_CTYPE with unset LC_CTYPE or set it explicitly to a valid locale e.g. export LC_CTYPE=en_US.UTF-8 (for sh/bash/zsh).

If you’re still having issues, please email