Implicit deny is the default security stance that says if you aren't specifically granted access or privileges for a resource, you're denied access by default.
Rule #1 allows the Accounting workstation to ONLY access the web server on the public network over the default HTTPS port, which is TCP port 443.
Rule #2 allows the HR workstation to ONLY communicate with the Financial server over the default SCP port, which is TCP Port 22 Rule #3 & Rule #4 allow the Admin workstation to ONLY access the Financial and Purchasing servers located on the secure network over the default TFTP port, which is Port 69.
References:
Stewart, James Michael, CompTIA Security+ Review Guide, Sybex, Indianapolis, 2014, pp. 26, 44 http://en.wikipedia.org/wiki/List_of_TCP_and_UDP_port_numbers References:
Stewart, James Michael, CompTIA Security+ Review Guide, Sybex, Indianapolis, 2014, pp. 26, 44 http://en.wikipedia.org/wiki/List_of_TCP_and_UDP_port_numbers