Not what you are looking for? Ask the experts!
Connection blocking with Sierra 10.12.4 and Security 7.3.1 b21
After upgrading Sierra to 10.12.4 I am now having an issue with command line network tools (ping, ssh, nslookup). Using any of these tools, such as pinging my default router, will result in the following intermittent behavior. The tool will hang (no output, but running top in another terminal window shows the process in a stuck state), then after a while it will produce output with the error "Operation not permitted". Other times, this will randomly work. I am running Security with the default settings. However, if I disable Firewall Connection Blocking, these issues go away. The issues are also not present when booted in safe made and Norton Security is not running. I had a colleague do a similar update and he is seeing the same issues, he uninstalled Norton Security to fix it on his machine.
This was not an issue prior to updating to 10.12.4.