What Is a Bastion Host on AWS?

What Is a Bastion Host on AWS?

AWS (Amazon Web Services) is a cloud-computing platform that provides many services. A bastion host on AWS is a server that acts as an intermediary between your public and private networks. It protects the private network by only allowing authorized connections to it, while still providing access to the public network via SSH or RDP. This blog post will discuss what a bastion host is and how you can get one set up for yourself!

What Is a Bastion Host on AWS?

Bastion hosts are virtual servers or machines that act as a layer of security by restricting access to the network. They provide entry points into your AWS account through which you can connect securely with other devices like VPCs, ECMs, and RDS instances. This allows you to control who has access to what in your network.

How Does a Bastion Host Work?

A bastion host on AWS acts as a restricted entry point into the network. In order to use it, an administrator must first create a security group and attach policies specifying which hosts are allowed access. When connecting from outside of the network, you’ll connect with SSH or RDP using your own personal key pair (or one provided by Amazon).

AWS users can choose between two options when setting up their bastion host: virtual servers (availability zones) or EC instances (Elastic Compute Cloud).

  • Virtual servers tend to be faster but lack advanced features like EBS volumes that come with EC instances. You also won’t need to pay for dedicated hardware; however, there is no guarantee how long they will stay online before needing to be replaced.
  • EC instances are more expensive but they come with features like EBS volumes, which you can use to store important data or applications. The instance also comes with a dedicated IP address and guaranteed uptime of 99.95%, making it easier for users to set up their connection without worrying about the availability of the server.

What Are Some Benefits of Using a Bastion Host?

Using a bastion host on AWS provides many benefits, including the following:

  • Allows you to create access policies for your private network. For example, if you want only certain IP addresses to be allowed in, it’s possible with EC instances and security groups.
  • Provides an additional layer of protection against hackers trying to gain unauthorized access into your system. A properly configured bastion host will have strict rules that limit what type of traffic is being sent between networks so no one can exploit vulnerabilities in applications or operating systems.
  • Helps ensure uptime because the connection doesn’t depend on any other server within the network (unlike using direct connections). This ensures users have more reliable SSH sessions even when there are issues with the network.
  • Allows you to connect with your private network even when the instance hosting it is down. For example, if an EC instance on AWS goes offline, you will still be able to connect using a bastion host because they are not directly connected.
  • Reduces latency issues since requests don’t have to travel between multiple servers in order to communicate with other hosts within the network (as opposed to routing).

What Are Some Disadvantages of Using a Bastion host?

There are also certain potential problems that come with using a bastion host on AWS, including:

  • Bastion hosts cannot be configured to use EBS volumes so you’ll need an external disk for storage (unless you’re willing to lose any data stored there during server failure). For EC instances this means higher costs because attaching additional disks will require more RAM and processing power.
  • May not fit into existing infrastructure if users rely heavily on direct connections between servers within their own VPC. You can still connect these types of networks together but it’s cumbersome without proper routing rules in place, which would defeat the purpose of using a bastion host – restricting access to your network.

AWS bastion host best practices

There are several best practices you should follow when implementing a bastion host on AWS. Many of these will depend on your specific use case; however, there are certain commonalities that apply in most cases.

  • Keep the number of access policies to a minimum by only allowing traffic from trusted sources
  • Avoid using proxy servers or gateways because they can cause problems with routing and connectivity issues
  • Ensure all generated keys have long lifespans so attackers don’t gain valid credentials if their key is compromised 
  • Use at least two layers of security to encrypt and decrypt traffic between your network and the bastion host
  • Install access logs that monitor all inbound and outbound sessions on the server (AWS does offer this service through CloudWatch)

Frequently Asked Questions:

Q. What is a VPC?

A. A Virtual Private Cloud (VPC) on AWS allows users to create their own virtual networks within the Amazon cloud so they have control over IP address ranges and how resources are accessed by other systems. For example, if an EC instance gets hacked into or compromised in some way then only that server will be affected without risking any damage to other servers hosted across the network using traditional connections with direct routes between them. This makes for better security overall because there’s less risk involved when deploying new instances/servers as well as making updates/changes since these changes won’t affect other servers.

Q. How much does a bastion host cost on AWS?

A. Bastion hosts don’t come cheap; however, they offer benefits like EBS volumes which make them more resilient than using direct connections between networks using EC instances alone. Depending on the type of configuration you use to set up your bastion host, it can be anywhere from $50 – $100 per month. 

Q. How does the cost of using a VPC change when compared to EC instances?

A. The most significant difference comes down to what you’re willing to lose – direct connections are more secure because they don’t rely on any servers within the network; however, this means that even one instance loss could cause connectivity issues. With a VPC, you can lose servers without it affecting your ability to connect with other hosts but this means that the network will be more vulnerable to attack since all traffic is routed through multiple servers and not just one central point of failure (like an EC instance).

Q. What other security measures should I consider?

A. It’s a good idea to implement multifactor authentication so credentials cannot be stolen if someone is able to breach your bastion host. You can also use CloudTrail logs which monitor all inbound and outbound traffic, set up automated alerts for suspicious activity, and encrypt all communications between networks using IPSec or SSH with self-signed certificates. AWS provides free tutorials on implementing these services.

Q. What do I need before creating my own bastion host?

A. The first thing you’ll want to do is set up a virtual private cloud so your server isn’t accessible from outside networks and ensure all outbound access rules are properly configured – otherwise users may experience problems when accessing resources on AWS or connecting their infrastructure together using VPNs/Direct Connect. You should also create IAM roles for any user accounts used by authorized parties as well as generate SSH keys for the bastion host to use for communication with other networks.

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