Stefferud was active in ARPA/NSF/IETF DARPA Internet research and development since 1975. He was involved in pre-standards work for X.400/X.500 in the International Federation for Information Processing (IFIP) WG 6.5, and post-standards profiling in the National Institute of Standards and Technology OIW.
Stefferud was a key figure in ARPA/NSF/IETF DARPA Internet research and development from 1975 onwards. He contributed to the early stages of X.400/X.500 standardization through IFIP WG 6.5, and later helped refine these standards at NIST OIW.