What are tagged and untagged ports?
Introduction
Back in the old days, there were no such things as managed switches. Instead, modern Ethernet connections were handled by simple devices called hubs. There were many older standards that predate Ethernet technology, such as token ring and ARCnet, but for our purposes, we will take a look at early Ethernet hubs.
You can think of an Ethernet hub as a single network segment that physically connects hosts to one another via a hardware link. This means that any device that connects to the physical port of the hub will have access to the network, provided they configure their device to match the segment that they are trying to connect to. This is great for ease of setup, but it is a nightmare for security.
Even worse, it opened the door for a major issue: collisions. Collisions occur when two hosts attempt to transmit data at exactly the same time. This happened quite often, as Ethernet communicates rapidly by human standards — many times per second. Cheaper hubs did not handle collisions very well and would sometimes need to be physically power-cycled or restarted in order to get them back up and running again.
An improvement over hubs came in the form of managed switches. Managed switches offer many advanced features such as port configuration and VLANs, which give much greater control and security over unmanaged switches and hubs.
If you are new to the world of networking, then you might have a few questions regarding VLANs. Perhaps the biggest stumbling block for newcomers to this side of networking is that they are a bit confused by how VLAN IDs relate to one another, how they connect segments of a network together and what they do. If you are already feeling a little lost, then don’t worry: we’ll be (Read more...)
*** This is a Security Bloggers Network syndicated blog from Infosec Resources authored by Graeme Messina. Read the original post at: http://feedproxy.google.com/~r/infosecResources/~3/mFNqUT3mrag/
