What Is Used To Create A Tunnel Across An IPV4 Network?

What Is Used To Create A Tunnel Across An IPV4 Network?

What Is Used To Create A Tunnel Across An IPV4 Network?

Networked computers use the Internet Protocol, version 4 (IPv4), to send and receive data packets. IPv4 is an addressing system that uses a numerical label assigned to each device connected to the internet. It acts as an identifier to locate other devices on the internet. The ID assigned to your computer is called the “IP address.” IPV4 addresses are 32-bits long and usually provided in “dotted decimal notation” (ex.

SSH Tunnels are used to create a secure connection in IPV4 Network. Both IPsec and GRE tunnels can be used to create a secure connection across an IPV4 network.


A tunnel is a mechanism that encapsulates data packets transmitted by some network protocol (e.g., IP) to be sent over another network or protocol.

For example, to carry Network layer (Layer 3) traffic through an intermediate network that does not support the same network layer protocol(s). Tunnels may serve as a hardware-assisted method of directly connecting two physically separate networks. 

A pair of communications protocols with different levels of abstraction are used for end-to-end connectivity: one residing at the lower level of the stack, which endows the communications with a specific network “layer” (e.g., IPv4) and another living at the upper level of this communication stack, that supports it with a particular application “protocol” (e.g., HTTP).

A tunnel is not encrypted by default unless you use SSL/TLS.


IPsec stands for “Internet Protocol Security,” a protocol suite that provides encryption and authentication services at the network layer between two hosts. IPsec is most commonly used in virtual private networks (VPNs), where it is implemented at the Internet Layer of the TCP/IP model.

Security Association (SA) is a set of policy rules that determine how traffic belonging to a security-aware connection will be handled. The SA specifies both what service(s) may be performed for such links and how such references must behave. 

There are two common types of SAs: transport mode and tunnel mode. Transport mode applies to filter to ensure that only packets matching an existing connection can pass through the device configured with this SA; no new links are allowed.

In IPsec, security associations (SAs) contain all of the required information to create a secure connection. The SA is essentially a set of rules that define how two devices will communicate securely and what type of packets they can exchange.

An IPsec tunnel provides Virtual Private Network over an insecure network such as IPV4.

It works by using Internet Protocol Security (IPSec). An IPsec VPN encrypts everything after the header has been removed; it does not add encryption between two devices or networks, creating a VPN tunnel like SSL or GRE do/can do. IPsec tunnels use IKE, ESP, and AH to implement complete end-to-end encryption, including data origin authentication data.

About GRE

Generic Routing Encapsulation (GRE) extends the protocol suite PPP, which allows encapsulation of many Network layer protocols inside point-to-point links. GRE is defined in RFC 2784 (in February 2000).

It has the advantage of preserving IP header information and attributes. At the same time, it is tunneled and maintaining the security features of Layer 2 Tunneling Protocol (L2TP) when implementing virtual private networks (VPNs).

GRE Key Points

IPsec tunnels use protocols like IKE, ESP, and AH to implement complete end-to-end encryption, including data origin authentication, data confidentiality, and integrity checks.

GRE does not provide any type of security/encryption for its payload. It needs another protocol that implements these three functions at the application level.

In a GRE tunnel, data from one network arrives encapsulated in IPv4 packets at the tunnel endpoint. 

The packet is decapsulated and then forwarded to its final destination. In this process, both source and destination addresses are rewritten.

Advantages Of Using A GRE/IPsec Combination

  1. It allows dynamic routing protocol to run over the tunnel interface
  2. It has less overhead than running IPsec in tunnel mode. It allows IP multicast traffic. 
  3. It requires a more restrictive crypto ACL to provide finer security control.
  4. Secure transport within an insecure network (IPv4).
  5. Can implement virtual private networks (VPN) in IPv4.
  6. IPsec provides data confidentiality, integrity check, and authentication header at the network layer, which can be used over any underlying transport.

Minimal Computer Hardware Requirements For An IPV4 Network

A network interface controller (NIC) is an expansion card that provides input/output functions required by the computer to process network data. NICs are typically installed on the motherboard, plugged into a slot.

An anonymous electronic mailing list is an email address to which anyone can send email without registering for an account or log in; the recipient must-read messages from the web interface or utilize automated mail handling software. 

A dynamic IP address constantly changes between sessions of USA active IP address changes between sessions of use, making it difficult for other users to locate this device on their local network.


In the real world, tunneling is a way to cross boundaries that can not be crossed without it. It is often used in VPNs. Likewise, in networking, tunnels are used for transporting data across networks. Packets are encapsulated in tunneling. The packets are wrapped inside other packets. 

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