Providing Network Professionals The Edge

Cisco 2800 Series ISRs – 2801, 2811, 2821, 2851 Features

The Cisco 2800 series of Integrated Services router platforms are one of my favorites due to their flexibility in accommodating a host of new and … [Read more...]

What is GARP (Gratuitous ARP Protection)?

Gratuitous ARP (protection) This is an example of a typical standards based (beneficial) LAN feature which can be used in some cases by the bad … [Read more...]

Configuring Voice VLANs (Catalyst 3750 and 3560)

In many cases clients would like to have their employee's PC connected directly to the 3-port switch on the back of the Cisco IP phone sitting on the … [Read more...]

Cisco Inline Power PoE Commands

Cisco (PoE) switches by default have their PoE (Power over Ethernet) enabled on every port.  This article shares some of the common CLI commands to … [Read more...]

Cisco Access Lists

Uses: Access Control NAT QoS Policy Routing Route filtering Demand dial routing   Rules: List is read from top to bottom … [Read more...]

OSPF Router ID

The OSPF Router ID: -Identifies the router to OSPF neighbors (#show ip ospf neighbor) -The highest physical interface is selected (the interface … [Read more...]

Configuring OSPF

Cisco OSPF Router Commands: -(config)#router ospf 1 (1 is a process ID between 1 - 65535.  It is locally significant) -(config-router)#network … [Read more...]

OSPF Hello Packets

OSPF Hello Packets contain the following information for neighbor relationships: -Router ID -Hello and Dead Timers ** -Network Mask … [Read more...]

Distance Vector Loop Prevention Mechanisms

1. RIP has a maximum allowed distance of 16 hops after which the route is considered invalid.  Therefore RIP can really be only used on small … [Read more...]

Cisco Switch Security Checklist

Security is a basic consideration which should always be kept in mind when building, engineering and deploying voice and data networks of any size. … [Read more...]