What are VLAN, NAT and private IP’s in computer networks?

Let us begin by learning about Virtual LAN (VLAN).

Virtual LAN (VLAN)

VLANs are logical grouping of devices which are in the same broadcast domain. Computers, servers, network devices are connected logically and their physical location don't matter. We use VLANs to manage traffic, to make the security improved.

A VLAN is used when multiple LAN devices are connected to each other, where each can sneak into the data transmitted by two devices, can be seen by a third device and security can be breached.

A VLAN will make sure that the data is kept only between two devices. It can be used to make a network simpler by grouping similar devices among each other.

Advantages of VLAN

  • ease of administration
  • confinement of broadcast domains
  • reduced broadcast traffic
  • enforcement of security policies
  • High performance and Reduced latency
  • low cost comparatively
  • Removes physical boundary
  • works on sensitive information
  • expansion and relocation of network

Disadvantages of VLAN

  • Management of VLAN is very complex

  • Problems may occur in interoperability

  • It cannot forward traffic to another VLAN

Network address translation (NAT)

NAT translates a set of IP addresses to another set of IP addresses.

A NAT is used in routers to preserve a limited number of IPV4 addresses. IPV4 are of two types mainly Public and Private.

Public IP Addresses are used to access the internet. One should have a public ip address to use the internet. Whereas, private ip addresses are used internally.

NAT is used when we need to translate a set of private ip addresses to a public ip address so that we can use the internet.

If someone on the Internet wants to connect to a computer on the private ip address, NAT will convert the public ip address to private ip address and then connect them.

Advantages of NAT

  • NAT increase security in a network. Because NAT creates a firewall between the organization's network and the public Internet.

  • NAT provides flexibility when connecting to the public internet.

  • NAT helps in providing IPv4 address space.

  • NAT provides more local control to administrators.

Disadvantages of NAT

  • Due to NAT, the end to end IP traceability is lost.

  • NAT also cause the delay in IPv4 communication.

  • some applications don't work when NAT is enabled.

Private IPs

Private IP is the set of IPs which are assigned by a router to the computers connected to them and they can only be worked within the local network. Some private IPs are reserved.

We use Private IP addresses to connect with local computers and in order to connect with the internet, private ip addresses are converted to public ip addresses by NAT and then we are able to use the Internet.

Private IP is used to connect to the Internet where a NAT converts it to public and then connects to the internet.