NTP makes me think of old spy novels and movies, where the team would set their analog watches to the same time, and say something like “On my mark, it will be 9:55… mark!”. NTP uses other [...]

#CDP has long been the default and favored protocol for a variety of device discovery functions, but LLDP offers an alternative as well. (LLDP is new to the exam topics per the May 2016 new CCENT [...]

IP uses Address Resolution Protocol (ARP) to discover the MAC address used by other hosts in the same subnet. Unfortunately, cybersecurity attacks often use legitimate protocols in unintended [...]

Dynamic Host Configuration Protocol (DHCP), like many network protocols, can be used as part of a cybersecurity attack. DHCP Snooping, a LAN switch feature, monitors DHCP messages flowing through [...]

The Dynamic Host Configuration Protocol (DHCP) protocol allows DHCP Clients to lease an IP address from a DHCP server. Simple enough. However, the protocol itself is open to various cybersecurity [...]

While most router interfaces use configured IP addresses, in some cases, a design calls for the router to dynamically learn an interface IP address. In those cases, routers can be configured to [...]

Most DHCP servers sit in a centralized location. To make that work, routers need to participate in the DHCP process to a small degree using a feature called the DHCP Relay Agent. For this lab, [...]

The Cisco switch Port Security feature lets the switch monitor incoming frames, look at the source MAC address, and determine whether frames with that source address should or should not be [...]

Sometimes, #CCNA studiers get bogged down with port security, focusing on all those little optional configuration settings. But what of the main feature: securing the port? This latest lab [...]

Quick, can you name all the small options available with Cisco’s port security feature on Catalyst IOS images? Most of us can’t, unless we’re in the middle of studying for CCENT, [...]