Bastion Host vs VPN vs Public SSH: Choosing the Right Access Model

Introduction

Bastion host vs VPN vs public SSH is a decision about how much access you expose, how much control you need, and how much operational overhead your team can realistically support. For most teams on Raff Technologies, the right answer is not whichever model sounds most secure in theory. It is the model your team can operate consistently without turning server access into either a risk or a bottleneck.

A bastion host is a hardened server that acts as a controlled gateway to private servers. A VPN is a private network access layer that connects an admin device into an internal network. Public SSH is direct server access over the internet, usually on port 22, protected by SSH authentication and firewall rules. All three can be valid. They just solve different access problems.

This matters because access design is where many cloud security mistakes start. Teams often expose SSH publicly because it is easy, then keep that same pattern long after they have multiple servers, multiple admins, and private services that should never have been public in the first place. In this guide, you will learn what each access model actually means, how they differ, which one fits which stage of team maturity, and how to apply the decision on Raff infrastructure. For broader context, keep Cloud Security Fundamentals for Developers nearby as the cluster pillar.

What These Access Models Actually Mean

The cleanest way to compare bastion hosts, VPNs, and public SSH is to stop thinking about them as competing brands of “secure access” and start thinking about them as three different exposure models.

Public SSH

Public SSH means the server is reachable from the public internet and accepts SSH connections directly. In practice, that usually means the server has a public IP, port 22 is open in some form, and access is protected by SSH keys, restricted source IPs, or other hardening controls.

This is the simplest model to understand and the fastest to deploy. That is why it is often the first choice for solo developers, small staging environments, and one-server workloads. When you follow the basics properly — key-based auth, disabled password login where possible, and strict firewall rules — public SSH is not automatically reckless. It is just direct.

The problem is scale. Direct public SSH creates a separate public administrative surface for every server that exposes it. That becomes harder to manage cleanly as the number of servers and admins grows.

Bastion host

A bastion host is a server whose job is not to run the application workload itself, but to act as the controlled jump point into private infrastructure. Instead of opening SSH on every internal server, you expose one hardened entry point and make the rest reachable only from private addresses or the bastion itself.

The main value here is control. A bastion host can centralize administrative entry, reduce the number of publicly reachable management endpoints, and make access policy easier to reason about. If you have multiple internal servers, databases, queues, or application nodes that do not belong on the public internet, a bastion host is often the first serious step beyond direct SSH.

The trade-off is operational overhead. You now have an extra host to patch, harden, monitor, and treat as critical infrastructure.

VPN

A VPN solves the access problem differently. Instead of creating one jump point to private servers, it extends private network access to the admin device itself. Once connected, the operator can reach internal resources over private addressing rather than through public administrative endpoints.

This is often the cleanest model when the team needs access to multiple internal services, not just SSH. Databases, dashboards, staging apps, metrics endpoints, internal APIs, and management interfaces all benefit from staying private and being reachable only after VPN authentication.

The trade-off is breadth. A VPN is powerful because it opens private reachability, but that also means poor segmentation or weak client hygiene can widen the blast radius if the VPN is not designed carefully.

The Real Difference: Where Access Control Lives

This is the key idea of the entire guide:

• With public SSH, access control lives mostly on each exposed server.
• With a bastion host, access control is concentrated at the gateway layer.
• With a VPN, access control shifts toward the private network boundary and client identity.

That distinction affects how your team manages risk.

Public SSH is easiest when infrastructure is small and every admin path can be hardened individually. Bastions are strongest when you want a narrow public administrative edge. VPNs are strongest when private-network access needs to cover more than just SSH.

A lot of confusion disappears once you frame the decision that way.

Side-by-Side Decision Framework

The practical takeaway is simple: the more you want internal systems to stay private, the less attractive direct public SSH becomes.

When Public SSH Is the Right Choice

Public SSH is still a valid choice when the environment is small and the access surface is easy to control.

1. You have one or two servers

If you are running a single app server, a personal development VM, or a small staging environment, public SSH is usually the lowest-friction option. You can keep the setup readable, restrict source IPs, enforce keys, and avoid adding a whole extra access layer before you need it.

2. Your team is small and stable

A small number of trusted operators with good key hygiene can run public SSH safely enough for many early workloads. The important part is not pretending that “small” means “no process.” You still need hardened SSH and a deny-by-default firewall posture. See Firewall Best Practices for Cloud Servers and How to Secure Your Ubuntu 24.04 Server.

3. The server is intentionally public-facing

Some servers already sit at the public edge, such as reverse proxies or web entry points. In that case, adding SSH hardening to the existing edge box can be more practical than introducing a bastion too early.

The mistake is not using public SSH. The mistake is keeping it as the default for every server long after the environment has outgrown it.

When a Bastion Host Is the Right Choice

A bastion host becomes the better answer when you want one narrow public management edge instead of several.

1. You have multiple private servers

If your application servers, databases, caches, and workers live on a private network, a bastion host gives admins one controlled way in without assigning public administrative reachability to each internal machine.

2. You want clearer administrative accountability

A bastion does not automatically solve logging and accountability, but it gives you a cleaner place to enforce them. This matters for small teams as soon as “who accessed what, and when?” stops being a casual question and starts being an operational requirement.

3. You want to reduce repetitive public hardening

Hardening one exposed gateway well is often more realistic than hardening five or ten SSH endpoints individually with the same discipline.

4. You do not need broad private resource access from every admin device

If the main goal is administrative hops into private servers, not full private-network reachability to many service types, a bastion is often simpler than a VPN.

When VPN Is the Right Choice

VPN becomes the stronger option when the team needs access to a private environment, not just a private shell.

1. Admins need more than SSH

If operators also need access to internal dashboards, databases, metrics systems, staging URLs, or API endpoints, a VPN is often cleaner than forcing everything through SSH tunnels or jump patterns.

2. You want internal services to remain private by default

This is especially relevant when you already accept the idea that databases, admin panels, and staging apps should not be internet-facing. The logic aligns closely with Private Networking in Cloud: Public vs Private Traffic and Understanding Private Cloud Networks.

3. You need a shared internal operating environment

When several team members need recurring access to the same internal network, a VPN often becomes operationally cleaner than routing every action through a single jump server.

4. You are ready to manage client-side access properly

A VPN adds client setup, key or certificate handling, segmentation decisions, and support overhead. That is why it is not automatically the best first step. It becomes the better step when the internal reachability value is worth the extra operational load. If you want the hands-on version, Raff already has Install WireGuard VPN on Ubuntu 24.04.

Common Mistakes Small Teams Make

Mistake 1: Calling VPN “more secure” without defining the threat model

A VPN reduces public exposure, but that alone does not guarantee a better access model. A badly segmented VPN can give too much internal reach, while a well-hardened public SSH setup can be appropriate for a small environment.

Mistake 2: Using public SSH everywhere because it worked at the start

What works for one server often becomes fragile at five. The danger is not the first shortcut. It is never revisiting the shortcut.

Mistake 3: Treating bastions as magic

A bastion host reduces exposure, but it is still a public-facing administrative asset. If it is weakly patched, broadly accessible, or poorly monitored, it becomes a concentrated risk instead of a control improvement.

Mistake 4: Ignoring network design

This decision only makes sense when paired with a real network model. If everything already sits flat on the public internet, the access model conversation is incomplete.

Best Practices and a Practical Decision Framework

Here is the simplest decision path I would use for a small team:

Choose public SSH when:

• You have one or two servers
• The admins are few and trusted
• You can enforce SSH keys, IP allowlists, and strong firewall policy
• The environment is not yet broad enough to justify extra access layers

Choose a bastion host when:

• Multiple private servers need administrative access
• You want one controlled public entry point
• You want to reduce direct public exposure on internal systems
• Auditability and access consistency matter more now

Choose VPN when:

• Admins need access to many internal services, not only SSH
• You want private-network access from operator devices
• Staging apps, dashboards, and databases should stay off the public internet
• Your team can support client setup and segmentation properly

Combine them when:

• The environment is larger or more sensitive
• You want a VPN for private service access and a bastion for tightly controlled admin hops
• You want to remove direct public SSH from internal servers entirely

That last point is important. Mature environments often do not “choose one forever.” They layer them.

Raff-Specific Context

On Raff, this decision maps naturally to the platform primitives you already have: Linux VMs, configurable firewalls, and private network routers. Raff’s public FAQ also makes the platform position clear: VMs support secure SSH key access, network isolation via configurable firewalls, and 2FA is available and recommended at the account level.

For many teams, the practical starting point is a General Purpose 2 vCPU / 4 GB / 50 GB NVMe VM at $4.99/month. That is enough for a test bastion, a WireGuard server for a small team, or a hardened admin box in a development environment. If you want steadier performance for a production admin gateway, the CPU-Optimized 2 vCPU / 4 GB / 80 GB tier at $19.99/month is the cleaner choice.

A reasonable Raff pattern looks like this:

• Keep only true edge services public
• Put application, database, and internal tooling traffic on private networking
• Start with hardened public SSH for very small environments
• Move to bastion or VPN when the infrastructure becomes multi-server and private by design

That is also why this guide belongs in the same cluster as Cloud Security Fundamentals for Developers, Understanding Private Cloud Networks, and Private Networking in Cloud: Public vs Private Traffic. They are all really answering the same bigger question: what should be public, and what should stay private?

Conclusion

Bastion host vs VPN vs public SSH is not a battle between “secure” and “insecure.” It is a decision about scope, exposure, and operational fit.

Public SSH is usually the best first answer when the environment is small and carefully hardened. Bastion hosts become the better answer when you need one controlled gateway into private servers. VPNs become the better answer when the team needs private-network reachability to many internal services, not just SSH sessions.

For most teams on Raff, the honest answer is this: start simple, harden early, and stop exposing administrative paths directly once the environment grows beyond what you can manage comfortably. That is the real threshold.

Next, pair this guide with How to Secure Your Ubuntu 24.04 Server, Install WireGuard VPN on Ubuntu 24.04, and Firewall Best Practices for Cloud Servers so the decision turns into a working access model instead of a theoretical one.