What is IPSec?

SSL is something we all know about. SSL is what allows e-commerce to flourish. SSL allows us to communicate securely with websites, but what if we need to connect privately to another network instead of a website? IPSec is the best choice.
Many new IT professionals and system administrators don’t understand IPSec. We all know that IPSec is a method of secure data communication. But what types of applications use it? How does IPSec function?
Let’s take a look at it today. This article will explain what IPSec does, what it’s for, how it works, as well as how it differs from SSL and TLS.
What is IPSec?
IPSec allows secure encrypted communications between clients and networks. This communication is sent over public networks, such as the internet. IPSec is used to connect two private networks and VPNs. IPSec is not a single protocol, but rather a collection. These protocols are:
Cisco VPNRelated Training from SPOTO
Start trainingAuthentication Header
Protocol for Encapsulating Security
Security Association
Internet Protocol

An Overview of IPsec [VIDEO]
Keith Barker discusses IPsec in this video. He compares and contrasts it with transport layer security. This video is a brief introduction to IPsec and its basic principles. It can be divided into IKEv1 or IKEv2.

What is IPsec?
IPSec allows clients to securely communicate with another network. This communication is not used for inter-device communication. It is instead used to connect a laptop to a private network using a public network such as the internet. IPsec can also connect to two private networks.
IPsec is not a protocol, but a collection of protocols that are used together. These protocols are:
Authentication Header
Protocol for Encapsulating Security
Security Association
Internet Protocol

Notice that we don’t use HTTP or TCP to communicate. IPSec travels through Layer 3 of the OSI network. This means that IPSec may be more secure than other methods for secure communication.
However, IPSec connections can still be established between the client/host through other networks. These networks are often public networks such as the internet. All communications between client and host are encrypted. Each new connection is not required to have encryption keys. Before connections can be established, both the client and host must know the private encryption keys.
This last bit is crucial. This is because all data in a packet is encrypted during communication. This includes the header.
You might assume that all packets must have readable headers in order to reach their destination correctly. ESP is used to do this. ESP adds new header information to the packet and trailers it (similar to headers, but at the end) for transport. The actual header remains encrypted.
Each packet is also authenticated. Each packet of data will be authenticated by the IPSec host. If not, the packet of data will be rejected.
What is IPSec used for?
IPSec allows secure communication between a client or host. This client could be a laptop. The client could also be a private internet. The host is usually a private network.
We now know how IPsec works. But what does IPSec do? What does the paragraph above mean?
IPSec is commonly used for VPNs. A VPN is a virtual private networks. A VPN allows a client to connect to a private network via the public internet. This is similar to an employee’s laptop. Once the VPN is established, the laptop of the employee can be connected to the private network.
A different way is to access the laptop.