Symantec has filed a patent infringement lawsuit against Zscaler, asserting violation of seven Symantec patents across a variety of network security technologies including web security, data loss prevention, threat prevention, access control and antivirus techniques. This lawsuit is based on U.S. Patent Nos. 6,279,113; 7,203,959; 7,246,227; 7,392,543; 7,735,116; 8,181,036; and 8,661,498.
https://www.symantec.com/about/newsroom/press-releases/2016/symantec_1212_01