Introduction One of the best practices in network security is to try and stop security threats from the entry-point of a LAN network. This means that the switch can play an important role in network security since it’s the entry-point of the network. For example, port- security on Cisco switches can be used to stop […]
Traffic Filtering on Cisco Layer3 Switches using ACL and VACL
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 Private VLANs on Cisco Switches
There are some situations where you have a single Layer3 subnet hosting several servers but you need to restrict network connectivity between the servers, although they reside in the same L3 subnet. This scenario is very common in hosting environments where you offer collocation for customers but for security reasons you want to keep their traffic […]
Cisco Switch Layer2 Layer3 Design and Configuration
Layer2 and Layer3 switches are the foundation of any network. After all, any network devices (routers, firewalls, computers, servers etc) have to be connected to a switch. Sooner or later, as a network engineer you will be faced with the task of deploying a switch network for a customer or for your own company. Therefore, learning […]
VLAN access-map (VACL) Example Configuration on Cisco Switch
In this post I will discuss Vlan access control lists (VACL), also called VLAN access Map or VLAN Map. A VLAN Access-map allows us to filter incoming and outgoing traffic in a switch Vlan. VLAN access-map configuration is very similar to the Route-map configuration. A Vlan access-map is placed on the whole Vlan, which means […]
Cisco Switching Products
Cisco Systems Inc. supports a broad range of local area network (LAN) switching architecture technologies and platforms. The general minimal requirements that the Cisco switching platforms are designed to address include the following: High-performance switched Ethernet, capable of delivering 100 Mbps and 1Gbps to the desktop, and 1Gbps or 10Gbps uplinks. Quality of Service (QoS) […]
Deleting the VLAN Database from a Cisco Switch
If you have your own Cisco switch equipment at your home lab or at your work environment you might have encountered the situation that you want to completely erase the whole switch configuration including any VLANs that are already configured on the switch (usually the vlan.dat file). In a Cisco switch, erasing the switch startup […]
Cisco Switch Network Design
I was browsing the Cisco support forum the other day and found the following question post which is about designing a Cisco switched network. Some useful answers are given, so I thought I would repost here for my blog readers. You will find useful tips about switch port dimensioning, redundancy etc. I Hope you find […]
Cisco Switches with Power over Ethernet PoE
Cisco has been supporting the standardized 802.3af power over ethernet feature since 2004. Catalyst switches with PoE are available as 10/100 PoE or even 10/100/1000 PoE. The Power over Ethernet feature is an excellent option for deployments of Cisco IP Phones. Wireless access points and security cameras can also be powered by PoE switches. The […]