How Does Internet Work

Saving VLAN.dat To NVRam – How to save VLAN.dat to different place – VLAN.dat redirection

Sometimes it can happen to you that the VLAN Database is lost when the switch is restarted. This is especially often when working in the lab environment. To help cross this issue you can tell the switch to save the VLAN.dat file to NVRAM instead of storing it to Flash. By default on Cisco switches that are running Cisco IOS the Flash memory is a default place to store VLAN.dat

Internet Relay Chat protocol is introduced in order to use for chat. Online users can perform synchronized text messaging with its help. In point of fact, users involved in chatting are required to install software at both receiver and sender sides that will perform the functions of decoding and putting on view the data by means of the IRC protocol, for example Pidgin.

In network security today, a firewall may be a software or hardware that makes a barrier between our internal network and untrusted external network. You can look at the firewall as a set of related programs that enforce an access control policy between two or more networks.

The name “firewall” is very strange, it has been originally used to describe the segment that separated the engine compartment from the interior of an automobile. In the networking world firewall is the first line of defense and the technology that will allow us to segment the network in physically separate subnetworks.

Cisco devices have many features that are good for something but they can be easily exploited. You must know that the Internet is full of people that want to exploit your network for different or no reasons. We will show you the best ways for thinking ahead and securing the layer 2 of the network – the switches. Let’s start…

Lightweight Directory Access Protocol

The purpose of LDAP introduction was to supply a directory service offering protocol. That protocol is active on a layer, resting on top of the TCP/IP stack. Its mechanism is available for the connection, searching, and modification of the Internet directories. Actually, Lightweight Directory Access Protocol (a directory service) is consisted on the client-server representation. The main job of that protocol is to the facilitate right of entry to an accessible directory.

Isolating Traffic inside a VLAN Using Private VLANs

In the article VACL – VLAN Access Lists we mention one way how to provide security on switch device like Cisco Catalyst switch. In this article we will see the other way of providing security with use of private VLANs – PVLAN.

The whole idea is to make possible to group VLANs inside the VLANs. You see from the picture here on the right that this will give you the opportunity to make group od computers or servers inside main (primary) VLAN. It will be possible to have two servers in the VLAN 10 and both of them on the same subnet. Here it becomes little bit strange, then they can be separated into two Secondary VLANs, VLAN 4 and VLAN 5.

If you are interested in the PVLAN configuration: PVLAN configuration article