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, download our PGP key.

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

  • Our mailing address:SIDNF.a.o. SIDN CSIRTPO Box 50226802 EA¬† ArnhemThe Netherlands


Bert ten Brinke

Security Officer

+31 26 352 5512

  • Tuesday 26 September 2017

    Internet security

    A fight on three fronts


    Our war on internet abuse

    Read more
  • Wednesday 17 April 2019

    About SIDN

    SIDN Labs researcher awarded doctorate for phishing study


    Elmer Lastdrager, research engineer SIDN Labs, spent six years studying various aspects of phishing. On 9 February, Lastdrager will be awarded a doctorate for his work.

    Read more
  • Tuesday 18 December 2018

    .nl domain name

    ICANN and the Whois: no more admin-c?


    A uniform global solution is wanted soon

    Read more


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