Cisco devices offer excellent features for traffic filtering. The classic Access Control List (ACL) is the core mechanism on Cisco network devices (routers, switches etc) which is mainly used for traffic filtering. In this article we will examine a different type of ACL, called the Vlan Access Control List (VACL) which works a little different […]
How to Configure Cisco Router-on-a-stick with Switch
In this post I will explain how to provide routing between two VLANs on a simple Layer 2 switch using a Cisco router with just one interface. This is called also Router-on-a-stick. This configuration is usually asked as a question in CCNA exams, so I hope it will be helpful for people preparing for certification. […]
Best Network Bandwidth Monitoring Software for Traffic Usage Monitoring
As network engineers we are usually assigned various tasks related to the life-cycle of networks, starting from the initial design, procurement, installation of network equipment and then management and monitoring of existing networks. In the latter phase (management and monitoring of networks) we are constantly faced with major or minor problems such as links going […]
How to Configure OSPF on Cisco Routers (With Example Commands)
Open Shortest Path First (OSPF) is a routing protocol developed by Internet Engineering Task Force (IETF). OSPF is standards-based which means it is available on routers by Cisco as well as other vendors, making it a vendor-neutral routing protocol. This is in contrast to Enhanced Interior Gateway Protocol (EIGRP) that is Cisco proprietary, and hence […]
18 Network Simulation Software Tools for Certification Practice or Research
Network simulation tools allow students (e.g people studying for Cisco Exams) to easily learn the core concepts of computer networking and TCP/IP in general. Even professionals could benefit from these tools by simulating network environments and get an idea of how a network will work before actual implementation. Moreover, system administrators could use them as […]
Cisco DHCP Snooping Configuration – What is DHCP Snooping?
Nowadays enterprises should deploy any available defenses they have available in order to eliminate, or at least minimize, possible attacks in their networks. Security controls should start from the network itself and span the whole IT infrastructure up to the application level. In this article I will describe a simple and effective security protection which […]
8 Different Types of Servers in Computer Networks
If you’re reading this article right now, you’ve already utilized the client-server model without even realizing it. You (as the client) have requested a resource (i.e this webpage) which was served to you by a webserver. This is the prevailing architecture for modern communications whereby digital data is offered by servers to clients. The alternate […]
Where to Buy Refurbished & Used Cisco Equipment (Switches, Routers etc)
Cisco devices are very reliable. I remember one day I run the command “show version” on a Cisco switch and showed me an uptime of around 8 years!! That switch was up and running for 8 years in a row without failing or being rebooted even a single time! There are thousands of Cisco devices […]
How to Configure Static Routing on Cisco ASA Firewall
Although the Cisco ASA appliance does not act as a router in the network, it still has a routing table and it is essential to configure static or dynamic routing in order for the appliance to know where to send packets. When a packet arrives to a network interface on the ASA firewall, the packet […]
Cisco Access List Configuration Examples (Standard, Extended ACL) on Routers Etc
An Access Control List (ACL) is a list of rules that control and filter traffic based on source and destination IP addresses or Port numbers. This happens by either allowing packets or blocking packets from an interface on a router, switch, firewall etc. Individual entries or statements in an access lists are called access control […]
13 Best Syslog Server Software (Free & Paid) for Windows/Linux
Syslog is the De Facto standard used in Networks for sending/receiving Log messages from IT systems, network devices, hosts etc. The Syslog protocol runs over port UDP 514 and is based on the IETF RFC 5424 standard. Almost all network connected devices (routers, switches, firewalls, Unix systems, Windows systems etc) support the Syslog protocol for […]
How to Configure IPv6 Address on Cisco Routers with Example
IP version 6 (IPv6) is the new version of the Internet Protocol (IP), intended to replace the older IPv4 which is still employed on the vast majority of Internet hosts. IPv6 increases the IP address size from 32 bits to 128 bits to support a much greater number of addressable hosts. IPv4 can support 232 […]
Configuring High Availability using HSRP and Boolean Object Tracking
In this tutorial we will see a special case of high availability scenario using HSRP with object tracking. Most modern enterprise networks in today’s deployments require some form of high availability depending on the uptime needed and the criticality of the service. The network infrastructure elements that are usually needed to be highly-availability include network […]