In enterprise networks, TACACS+ (Terminal Access Controller Access-Control System Plus) remains a go-to protocol for securing administrative access to routers, switches, firewalls, and other infrastructure devices. It offers granular control over authentication, authorization, and accounting—especially when compared to RADIUS.
Traditionally, TACACS+ has been associated with on-premises servers and proprietary vendor solutions (like Cisco ISE), which can be expensive, complex to manage, and rigid to scale. For teams looking to cut licensing costs, reduce vendor lock-in, or simply explore more agile alternatives, both open-source and cloud-based options are increasingly appealing.
Let’s take a look at a few of the top open-source TACACS+ options—then we’ll explore why a cloud-native approach, like Portnox Cloud TACACS+, might be the smarter long-term choice.
Top Open-Source Alternatives to TACACS+
1. FreeRADIUS (with TACACS+ Support)
While primarily a RADIUS server, FreeRADIUS can be extended to support TACACS+ with third-party modules or patches. It’s ideal for hybrid environments or organizations that want to experiment with AAA flexibility.
Pros:
- Mature ecosystem with robust support
- Flexible back-end integration (LDAP, MySQL, Active Directory)
- Highly customizable
Cons:
- No native TACACS+—requires external add-ons
- Configuration can be complex, especially for beginners
2. tac_plus (Shrubbery Networks)
A popular, lightweight, open-source TACACS+ daemon often used in lab and production environments alike. It works well with Cisco gear and offers decent performance with low resource overhead.
Pros:
- Simple setup for Unix/Linux admins
- Command-level authorization supported
- Free and actively maintained
Cons:
- No built-in web UI or role-based access
- Limited support for modern identity sources
3. OpenTACACS+
A fork of the original Cisco TACACS+ source code, OpenTACACS+ keeps things simple and minimal. It’s best suited for testing, learning environments, or very small deployments.
Pros:
- Lightweight and easy to deploy
- Compatible with many Cisco-style configs
Cons:
- Limited community and development activity
- Not ideal for enterprise-grade security or scalability
Why Cloud-Based TACACS+ Changes the Game
While open-source TACACS+ servers can serve well in small to mid-size environments, they come with the usual baggage: configuration complexity, manual updates, self-hosted infrastructure, and limited visibility.
That’s where cloud-native TACACS+ solutions—like Portnox Cloud TACACS+—stand out.
Advantages of Portnox Cloud TACACS+:
- No hardware or server maintenance – Instant deployment with zero infrastructure.
- Modern identity integrations – Seamless connection with cloud-based identity providers (Azure AD, Okta, etc.).
- Full visibility & logging – Centralized reporting and auditing without manual log scraping.
- Scalable across locations – Perfect for distributed teams and branch networks.
- Granular policy control – Command-level authorization, just like traditional TACACS+, but without the config headaches.
Unlike open-source tools that require CLI kung fu, Portnox offers a modern UI, streamlined policy creation, and cloud-first design that fits today’s hybrid work models.
When to Choose Open-Source vs. Cloud TACACS+
| Use Case | Best Fit |
| Lab/testing environments | OpenTACACS+, tac_plus |
| Budget-constrained SMBs | tac_plus, FreeRADIUS |
| Security at scale with ease | Portnox Cloud TACACS+ |
| Cloud-native, hybrid IT teams | Portnox Cloud TACACS+ |
| Legacy infrastructure-only teams | FreeRADIUS + scripting |
Open-source TACACS+ solutions can absolutely get the job done, especially in lean or DIY-driven environments. But as networks grow, diversify, and move toward the cloud, so should your access control strategy.
Cloud-based TACACS+, like what Portnox offers, delivers the same powerful AAA control—without the overhead. It’s secure, scalable, and ridiculously easy to deploy.
In short: if you’re tired of managing AAA the hard way, the cloud has your back.