What is Policy-Based Routing and why to use it? Policy-based routing (PBR) is a technique used to make routing decisions based on policies set by the network administrator. When a router receives a packet it normally decides where to forward it based on the destination address in the packet, which Read more…
What are static routes and why to use them? Static routing is a form of routing that occurs when a router uses a manually-configured routing entry, rather than information from a dynamic routing traffic. In many cases, static routes are manually configured by a network administrator by adding in entries Read more…
What is NAT and PAT and why to use them? Network Address Translation (NAT) in its most simple form is a method of translating a one IP address to another. For example a public IP address is translated to a private IP address and vice versa. Without NAT computers on Read more…
What is OSPF and why to use it? Open Shortest Path First (OSPF) is interior gateway protocol (IGP) that makes use of a link state routing (LSR) algorithm. OSPF supports complex networks with multiple routers and may be structured, or subdivided, into routing areas to simplify administration and optimize traffic and Read more…
What is IP SLA and why to use it? ISP failover is the ability to failover from one ISP to another, or more specifically from one route to another, in order to ensure availability and access. In order to facilitate this functionality we must use a feature called IP SLA . IP Read more…
What is VRRP and why to use it? Virtual Router Redundancy Protocol (VRRP) is an election protocol that dynamically assigns responsibility for one or more virtual routers to the VRRP routers on a LAN, allowing several routers on a multiaccess link to utilize the same virtual IP address. A VRRP Read more…
What are Access Control Lists and why to use them? An access control list is a rule, or can be comprised of one or more rules, that are applied to an interface allowing hosts to communicate to other hosts by filtering traffic using specific protocols such as tcp, udp, icmp Read more…
What are stub networks and why to use them? A stub network is a term describing a computer network part of a large whole that will typically send much or all of its non-local traffic out via a single path. Stub networks are usually only aware of a default route Read more…
What are Zone-Based Firewalls and how to use them? Zone-Based Firewalls (ZBF) is a firewall methodology of placing interfaces into zone and defining traffic definitions to allow traffic to pass or drop. In the past firewalls were comprised of access-list that would define both source and destination as well as Read more…
What are VRFs and why to use them? Virtual Routing and Forwarding (VRF) is an IP technology that allows multiple instances of a routing table to coexist on the same router at the same time. Because the routing instances are independent, the same or overlapping IP addresses can be used Read more…