 In June 2001 , triggered by concerns over Darren Reed 's modification of IPFilter 's license wording , a systematic license audit of the OpenBSD ports and source trees was undertaken . Code in more than a hundred files throughout the system was found to be unlicensed , ambiguously licensed or in use against the terms of the license . To ensure that all licenses were properly adhered to , an attempt was made to contact all the relevant copyright holders : some pieces of code were removed , many were replaced , and others , such as the multicast routing tools <unk> and map @-@ <unk> , were relicensed so that OpenBSD could continue to use them . Also removed during this audit was all software produced by Daniel J. Bernstein . At the time , Bernstein requested that all modified versions of his code be approved by him prior to redistribution , a requirement to which OpenBSD developers were unwilling to devote time or effort . 
