The Computer Security Incident Response Team (CSIRT)

We investigate all security breaches on our ICT infrastructure.

What is our mission?

Our mission is to provide SIDN with proactive and reactive support by maintaining and continually seeking to improve the security of our services.

What are our goals?

  • We are the single trusted point for computer security matters.

  • We promote awareness of computer security issues.

  • We make recommendations regarding computer security.

  • We support the resolution of computer security incidents.

  • We actively address threats to our services.

What do we protect?

What are we responsible for?

  • The Domain Registration System

  • The resolving of .nl domain names

  • The .nl name servers and zone file

  • The Is and Whois for .nl domain names

  • Our websites (both public and restricted access)

  • The technical infrastructure that secures our offices

  • All other ICT infrastructure

How can you reach us?

  • Preferably by e-mail:

  • If you want to encrypt your message? The PGP key is currently being replaced. We apologize for the inconvenience.

  • You can call us between 08:30 and 17:00 (Dutch time) on +31 26 352 5512.

  • Our mailing address: SIDN F.a.o. SIDN CSIRT PO Box 5022 6802 EA¬† Arnhem The Netherlands


Bert ten Brinke

Security Officer

+31 26 352 5512

  • Monday 17 February 2020

    Internet security

    Nearly 4,500 fake webshops taken down in 2019 following detection by SIDN


    Self-teaching detection tool now 79.3 per cent accurate

    Read more
  • Wednesday 6 November 2019

    Internet security

    Implementation of existing standards would make the internet much more secure


    "Software suppliers and service providers should be addressed individually"

    Read more
  • Wednesday 24 July 2019

    Knowledge sold for $ 30 million


    Business lessons from the world's most expensive domain name

    Read more


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