Tag: tunneling

Intro

IPsec makes VPN connection possible. I enables to simulate a leased line across public Internet and thus enable us to get secure connection across unsecured environment. It enables encryption, authentication and protection of our data when sent across insecurity of the world’s biggest internetwork – Internet.

It’s the cheap way to simulate a leased line, the way to send private data across the public network without compromising privacy. The goal of IPsec is to secure services and lower the cost of data transfer. Try to compare it to pricing of data transfers across dark cables / leased lines.

There are two parts of IPsec security suite
– ESP – Encapsulating Security Payload
– AH – Authentication Header

Based on our situation we can configure two different modes of operation and here we are to make the things clear about the differences and the technology behind those modes.

IPSec Transport Mode and Tunnel Mode

As the time goes by and the network with more and more virtualised servers and other devices are making that network more complicated, overlay technologies are rising to save the day for network administrators.

Virtual Extensible LAN – VXLAN is a new encapsulation technology used to run an overlay network on current Layer 3 communication network. An overlay network is considered as a practical network that is set up on the top of current layer 2 network. It also considers additional layer 3 technologies to aid flexible computer architectures. VXLAN will make sure it is very easy for network engineers to level out the right cloud computing setting while reasonably separating cloud applications and tenants. A cloud computing environment is defined as a multitenant, every tenant needs its separately configured logical network, which in return needs it’s very own network ID or identification.

What the hell that means?

What it this VXLAN doing actually. To put it simple, VXLAN can create logical network to connect your virtual machines across different networks. It is enabling us to make a layer 2 network for our VMs on top of our layer 3 network. That’s why VXLAN is a overlay technology. In “normal” network if you are connecting virtual machine to get the connection to some other virtual machine on different subnet, you need to use a layer 3 router to make a connection between networks. With VXLAN we can utilize VXLAN gateway of some sort to connect them without even exiting into physical network.

Image: VXLAN frame – taken from blog.cisco.com website

L2TP Attributes Summary

Projected L2TP standard was made available in the year 1999 by means of RFC 2661. It was originated primarily from two different tunneling protocols, named as: Point-to-Point communication protocol and PPTP (Point to Point Tunneling protocol). In other words, L2TP (Layer 2 Tunnel Protocol) is an up-and-coming IETF (Internet Engineering Task Force) standard that came in front with the traits of two on-hand tunneling protocols, named as: Cisco’s L2F  (Layer 2 Forwarding) and Microsoft’s PPTP (Point-to-Point Tunneling Protocol). L2TP protocol is actually an expanded form of the PPP (a significant constituent for VPNs).

A VPN (virtual private network) offers network connection possibility over an extensive physical distance (remoteness). But you need to know that it can work over both on private networks and public networks (Internet).

VPN in simple words make possible for clients or whole LAN-s on other side of the internet to connect into main LAN pesmises and have the “technical impression” that they are localy connected to this site. This includes gaining the local IP address from local DHCP pool, possibility to use all the LAN resources that are defined by the administrator etc.