Dear all, I'm the system admin of a web server and I found these errors in my apache logs: [Tue Feb 07 10:35:08 2012] [warn] (43)Identifier removed: Failed to release SSL session cache lock [Tue Feb 07 10:36:04 2012] [warn] (43)Identifier removed: Failed to acquire SSL session cache lock [Tue Feb 07 10:36:04 2012] [warn] (43)Identifier removed: Failed to release SSL session cache lock [Tue Feb 07 10:36:05 2012] [warn] child process 21599 still did not exit, sending a SIGTERM [Tue Feb 07 10:36:06 2012] [notice] caught SIGTERM, shutting down also some traces of Dfind web scanner: [Mon Feb 06 05:54:01 2012] [error] [client 88.46.75.27] client sent HTTP/1.1 request without hostname (see RFC2616 section 14.23): /w00tw00t.at.ISC.SANS.DFind:) I have added a rule into my iptables to block this and so far so good However I don't know how these "failed to release SSL session cache lock" managed to bring my apache server down and if they are somehow related to these Dfind scans. Any ideas? Regards, Miguel