Over the years, Lars-Johan has specialized in the domain name system, starting with administration of DNS databases using the Berkeley Internet Name Daemon (BIND), and continuing with the more theoretical side of things like operational issues and standardisation of protocols. On the e-mail side his interest in the Berkeley Unix sendmail program has taken him on a similar path.

Lars-Johan's current functions include:

• Responsible for i.root-servers.net, the first non-US root name server,
• member of ICANN's Root Server System Advisory Committee,
• designer and maintainer of DNS systems for the Swedish top-level domain .se,
• chairman of the DNSOP working group in the Internet Engineering Task Force standardization body,
• memeber of the IETF DNS Directorate,
• active in the DNSEXT working group in the Internet Engineering Task Force standardization body,
• active in the DNS working group in the European Internet service provider forum RIPE,
• member of the gTLD-MOU Policy Oversight Committee,

• member of the program committee for the ICANN meeting in Los Angeles.
• teacher on KTHNOC's course in Advanced Internet Design.
• maintainer of DNS and mail software for central DNS and mail servers at the Royal Institute of Technology,
• chairman of the working group for development of new domain name rules for the Swedish top-level domain .se,
• assistant supervisor for the Internet Mail Consortium's mail interoperability tests,
• supervisor for the Swedish Network Users Society's mail interoperability tests,
• assistant investigator at the Swedish Agency for Administrative Development.