revision 1.67.2.1 で対応してみた。
--ssl use POP over SSL with --pop option --ssl-cert filename|dirname specify a filename of a certificate of a trusted CA or a name of a directory of certificates
% ./bsfilter -v --ssl --ssl-cert ~/.certs/ddc328ff.0 --pop --pop-server pop.gmail.com --pop-port 995 start Sat Feb 19 00:50:08 JST 2005 pop mode start Sat Feb 19 00:50:08 JST 2005 pop_proxy is on 10110:0.0.0.0:0.0.0.0 #<TCPSocket:0x8102a60> is accepted #<TCPSocket:0x8102830> is connected /home/nabeken/.certs/ddc328ff.0 is used for SSL ca_file #<OpenSSL::SSL::SSLSocket:0x8102790> is connected #<TCPSocket:0x8102a60> is gone #<OpenSSL::SSL::SSLSocket:0x8102790> is gone