John held the John H. Weitnauer, Jr., Chair in the School of Electrical and Computer Engineering at the Georgia Institute of Technology from 1993-2016, and was also a Georgia Research Alliance Eminent Scholar. In 2000 he invented the Stealthwatch system for network security monitoring, and founded Lancope, Inc. He served as Chairman of Lancope, Inc. from 2000-2006. He raised over $25M in venture capital for Lancope before it was acquired by Cisco in 2016 for $453M. He has also served as Director of the Georgia Center for Advanced Telecommunications Technology (GCATT) from June 1993 to Nov. 1996.