Configuration Tips

Route reflectors became an essential part of any larger internet service provider’s environment. It would be hard to imagine multiple routers running BGP in full mesh topology these days when scalability is the key. The complete route reflector concept can be found in RFC4456, which dates back to 2006. It’s very …

Thinness and thickness are architectural concepts, to the point that both types of routers might even be virtualized. Strictly speaking, thin and thick routers is SDN (Software Defined Network) jargon rather than industry standard language. These terms are getting more and more widely used and they are so meaningful and …

Hot Standby Routing Protocol (HSRP) is a Cisco proprietary default gateway redundancy protocol. If the primary gateway fails, HSRP automatically redirects hosts to the the backup gateway. HSRP has been covered in few RouterFreak’s articles such as: Comparing HSRP vs VRRP How to configure HSRP on a Cisco router First Hop Redundancy …

Running a reliable and fast network is not something that just happens. It requires the right tools and the right skill sets to tackle the steps to reduce the number of problems that occur, and when they do occur resolve them in a timely manner. Many problems can be prevented …

This article describes the configuration of an interesting network scenario that is applicable in many real world situations, mainly in small to medium networks. We have three different internal LAN networks which host user computers and other IT infrastructure (servers, network printers etc). We want to separate the three internal …

In this article we are going to explain what the ip subnet zero is, but first we need to introduce subnetting. The Subnetting is used to partition a network into sub-networks (also called subnets) that are smaller in terms of addressing space. The first and the last subnets calculated during the …

Although there was the ARPANET before it, the internet as we know it today came about in the early 1980s when TCP/IP was invented. Even back then, the nascent internet was a network of networks, and those newfangled IP packets needed to be routed from one organization’s network to another …

If you decided to read the content of this post, you probably know something (or a lot) about Border Gateway Protocol (BGP) and its benefits. Or I might be wrong, and you have heard about this cool protocol numerous times, but just did not figure out how it works. In either …

The Cisco ASA 5505 Firewall is the smallest model in the new 5500 Cisco series of hardware appliances. Although this model is suitable for small businesses, branch offices or even home use, its firewall security capabilities are the same as the biggest models (5510, 5520, 5540 etc). The Adaptive Security …

Have you secured your router with an ACL for SNMP access but are still seeing pages of SNMP-3-AUTHFAIL messages in your logs? In this article we will be dig into this issue and find out exactly what’s going and and why an SNMP-3-AUTHFAIL message might showing up in your logs …