Wietse is known for his software such as the TCP Wrapper and the Postfix mail system. He co-authored the SATAN network scanner and the Coroner’s Toolkit (TCT) for forensic analysis, as well as a book on Forensic Discovery. Wietse received awards from the Free Software Foundation (FSF), the System Administrator’s Guild (SAGE), the Netherlands UNIX User Group (NLUUG), the Information System Security Association (ISSA), as well as a Sendmail innovation award. He served a two-year term as chair of the international Forum of Incident Response and Security Teams (FIRST).