What Is iptables and How to Use It for Network Security?

iptables is a command-line firewall utility that is used to manage the Linux kernel’s built-in firewall. It allows administrators to configure rules that control how packets are handled by the kernel’s networking stack. These rules can be used to allow or block incoming or outgoing traffic based on various criteria, such as source and destination IP addresses, ports, and protocols.
The iptables firewall operates by defining a set of chains, which are groups of rules that are applied to incoming or outgoing network packets. The most commonly used chains are the INPUT chain, which is applied to incoming packets, the OUTPUT chain, which is applied to locally-generated packets, and the FORWARD chain, which is applied to packets that are being forwarded through the machine.
Each chain is made up of a series of rules, which specify what action should be taken for packets that match certain criteria. The rules are processed in order, and the first rule that matches a packet is the rule that is applied. iptables supports many different matching criteria, such as IP addresses, ports, and packet headers, as well as various actions, such as dropping or accepting packets, and logging or redirecting packets to other chains.
Iptables is powerful tool that is widely used to configure the firewall on Linux systems, It’s important to note that it is not the only firewall solution on Linux, another alternative is nftables which is replacement of iptables and provides a more powerful and flexible firewall solution than iptables.

Why use iptables?

There are several reasons why you might use iptables to configure a firewall on a Linux system:

  1. Security: One of the primary reasons to use iptables is to improve the security of a system by controlling which network traffic is allowed to reach it. With iptables, you can set rules to block incoming traffic from known malicious sources, and only allow traffic from trusted sources.
  2. Access Control: Iptables can also be used to control access to services running on a system. For example, you can use iptables to only allow incoming connections to a web server from specific IP addresses or subnets, or to block incoming connections to a service on a specific port.
  3. Traffic Management: Iptables can be used to manage the flow of network traffic on a system. You can use iptables to prioritize certain types of traffic, such as real-time applications, or to limit the amount of bandwidth that a specific IP address or service can use.
  4. NAT: Iptables is capable of performing NAT (Network Address Translation) which enables devices on a local network to access the Internet through a single public IP address. It can also be used to forward specific ports to internal servers on a network, allowing them to be accessed remotely.
  5. Provide a base for other tools: Iptables can be integrated with other tools such as fail2ban and ufw, which can be used to simplify the management of firewall rules.
  6. Advanced use-cases: iptables offers much more flexibility and granularity in terms of filtering packets, providing advanced use cases that other firewalls may not provide.
    It is worth noting that while iptables is a powerful and flexible tool, it can be complex to set up and manage, especially for large or complex networks. It is important to have a good understanding of network security and Linux administration before configuring a firewall with iptables.

How to Use iptables?

  1. Viewing the current firewall rules: To view the current firewall rules, you can use the iptables command without any options or arguments. This will display the current rules in all of the default chains (INPUT, FORWARD, and OUTPUT).
  2. Adding a new rule: To add a new rule to the firewall, you can use the iptables command with the -A option, which stands for “append.” For example, to allow incoming SSH traffic, you can use the following command:
iptables -A INPUT -p tcp --dport 22 -j ACCEPT

The above command will append a rule to the INPUT chain that allows incoming traffic to TCP port 22 (the default SSH port) and will match packets that are “jumped” to the ACCEPT target

  1. Deleting a rule: To delete a rule, you can use the iptables command with the -D option, which stands for “delete.” For example, to delete a rule that allows incoming SSH traffic, you can use the following command:
iptables -D INPUT -p tcp --dport 22 -j ACCEPT

This will delete a rule from the INPUT chain that allows incoming traffic to TCP port 22 and jumps packets to the ACCEPT target

  1. Saving firewall rules: To save the current firewall rules so that they will persist after a reboot, you can use the iptables-save command to save the current rules to a file, and then use the iptables-restore command to restore the saved rules on reboot.

iptables-save > /etc/iptables.rules

This will save the current firewall rules to /etc/iptables.rules file, and it could be automatically restored by systemd on startup.

  1. Clearing all the firewall rules: If you want to clear all the rules that are currently set in the firewall, you can use the iptables command with the -F option, which stands for “flush.”

iptables -F

This command will flush all the chains, so all the rules in all chains are deleted

It’s important to note that the commands above are basic examples and that iptables can be customized to suit more complex needs and scenarios, such as configuring a firewall for a server, blocking specific IP addresses, and creating custom chains.

VPS VS VDS . Which one is right for you?

When buying a virtual private server, you want to know what is the difference between VPS and VDS . At first glance, a VDS or Virtual Dedicated Server looks like a fancy label for a high-end VPS. This is not really the case VDS can be considered a VPS in some circles depending on who you ask. Virtualization technology is widely used by businesses around the world. Virtualization is nothing new. In fact, these technologies have been around for over a decade and have been developed by software vendors such as Microsoft and VMWare. Server virtualization is so advanced that some experiments show that virtualized servers can compete with servers made on bare metal. There are many differences between traditional VPS and professional hosting VDS.

VDS: Virtualization Server Instance Connected to a Single Server typically uses a dedicated server and distributes it to multiple virtual servers. All servers can be configured to have multiple VPS virtualization systems. The difference between VPS and VDS is simple. An example VDS contains all servers while a VPS is a server configured to host multiple servers. A VDS configuration essentially provides server support, but the virtualized process relies on the server itself. VDS can be easily confused with bare metal servers. A VDS is made up of all the servers that act as nodes in a hypervisor. Services in this manner can provide good organization with regular VDS hosting experience.

VPS: Virtualized Server Instance Sharing Server As described above, a virtual private server is just an instance server created by a hypervisor. To identify a server-based VPS, the hypervisor divides a single server into multiple servers. Examples of this type is purchased with the VPS plan. These capacities do not change because different VPS servers can be hosted on the same physical server. The virtualization process ensures that the VPS has the unique capabilities that were purchased. The difference between VPS and VDS is that VDS brings unique servers into the virtualization process where the VPS shares the main server with other private servers created on the same node.

What is best for you? VPS or VDS? The answer to this question depends on the needs of your organization. For memory and CPU heavy workloads, organizations may find it easier to let a dedicated server is not sharing memory or CPU capacity with other private servers in the box. . But If you have a small to medium sized business, you can start with a VPS to measure its performance. If your application fails, you can upgrade your VPS plan to a VDS. Because these services have stronger processing capacities, In CryptoVPS we provide VDS with dedicated CPU cores .

Advantages of a Linux VPS and Why use it.

Just like the windows and mac etc. Linux is one of the favorite operating system many users use it on their desktops and laptops and performs all the functions like bootloader, shell, manages the graphics and many other basic options.

VPS stands for virtual private server that offers the bridge between dedicated resources.

Now a days VPS becomes the preferred for hosting a website or web applications for small and the medium size businesses. VPS creates the virtualization on a dedicated server that is completely independent and act like as an dedicated server. Linux VPS has its own partition of operating system and disk space. Normally physical servers are kept in the data centers to give the services of VPS to the users.

Uses of a Linux VPS

Many shared hosting users prefer Linux VPS to have more control over their environment. On the other hand, users can have advanced user access to the operating system. VPS users should have an advanced level of experience with managing linux commands. Linux VPS hosting provides cost effective shared hosting solution for better and easier operation.

Why use Linux VPS? As Linux VPS provides an open source operating system for developers around the world, it gives you more and more power to manage operations to run your business, manage mail and add websites. You can exercise your security policies. You can develop the operating system controls you choose and you can create the rules you want to better run your business in accordance with your company policies. It also provides advanced storage and superior disk performance.

Advantages of Linux VPS

In general, the feature set of a VPS varies from provider to provider. When it comes to Linux VPS connectivity, Linux based VPS has many advantages over other OS based VPS which define their differences. Now we are going to see the incredible benefits of Linux based VPS. When it comes to resource allocation, Linux provides the best platform in this regard because you can enjoy faster loading. Linux VPS provides more disk space and more efficient use of RAM and basic performance. Moreover Linux servers can be powered on for a longer period of time without freezing issue that we might experience with other Operating systems.

Root access will be provided, but you can make your choice.

The open source platform gives you complete control over the configs, though you can manage the actions via the best interface panel.

Monitoring is one of the other obvious benefits of using the VPS service, which ensures the physical health of the server and alerts you to suspicious activity if detected.

More importantly you can create separate email accounts to manage different dedicated resources.

In CryptoVPS we provide World class Linux VPS servers with the cheapest price in the market which you can buy with Cryptocurrency of your choice completely hassle free!