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Networking · head to head

OpenVPN vs PRTG Network Monitor

OpenVPN logo

OpenVPN

Networking

Open source VPN protocol with a commercial Access Server product priced per simultaneous connection

From
Free
Rated
-
Full reviewWebsite
PRTG Network Monitor logo

PRTG Network Monitor

Networking

Infrastructure monitoring licensed by sensor count, not by device, which changes what a licence actually covers

From
On request
Rated
-
Full reviewWebsite

The short version

  • Only OpenVPN has a free tier, so it costs nothing to try first.
  • Each has a real cost: OpenVPN open source OpenVPN, while free, requires real technical skill to configure, secure and maintain without the Access Server admin layer; PRTG Network Monitor licensing by sensor rather than device means the real cost per device is unpredictable until sensor density is measured; a small network of complex devices can need a much larger tier than device count alone suggests
  • They diverge on capability: OpenVPN covers Open source core, PRTG Network Monitor covers Sensor-based monitoring.
  • Prices and features above were last checked on 1 September 2026.

Where they differ

Only the attributes on which OpenVPN and PRTG Network Monitor actually diverge.

Attributes where OpenVPN and PRTG Network Monitor differ
AttributeOpenVPNPRTG Network Monitor
Starting priceFreeOn request
Pricing modelOpen source core is free; Access Server billed per simultaneous connectionPer sensor tier, billed monthly on an annual contract
Free tierYesNo
PlatformsLinux, Windows, macOS, iOS, AndroidWindows, Web, iOS, Android

Identical on both: user rating (Not yet rated), category (Networking).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in OpenVPN

  • Open source core
  • Access Server admin UI
  • Per-connection licensing
  • Free tier
  • Cross-platform clients

Only in PRTG Network Monitor

  • Sensor-based monitoring
  • Auto-discovery
  • Multiple monitoring technologies
  • Maps and dashboards
  • Cloud and hybrid deployment

What people use each for

The jobs each tool is most often brought in to do.

OpenVPN

  • A technical team wanting a fully free, self-configured VPN server using the open source protocol without any vendor relationshipnot PRTG Network Monitor
  • A small business wanting a supported, easier-to-administer VPN server, willing to pay per concurrent connection rather than per employeenot PRTG Network Monitor
  • An organisation with more staff than typical concurrent VPN usage, since Access Server bills only active simultaneous connections, not total accountsnot PRTG Network Monitor
  • An IoT or large-scale deployment needing custom Enterprise pricing above 2,000 connectionsnot PRTG Network Monitor

PRTG Network Monitor

  • An IT team wanting network, server and application monitoring in one product rather than assembling separate open source toolsnot OpenVPN
  • An organisation that wants a Windows-installable on-premises monitoring server with a polished UI out of the boxnot OpenVPN
  • A team sizing a monitoring purchase that needs to calculate sensor density per device carefully before committing to a tiernot OpenVPN
  • A company wanting hybrid on-premises and cloud monitoring from the same licence and dashboardnot OpenVPN

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

OpenVPN

  • Open source OpenVPN, while free, requires real technical skill to configure, secure and maintain without the Access Server admin layer
  • Per-connection billing on Access Server means usage spikes, such as an all-hands remote day, can push simultaneous connections over a licensed limit and block new connections until usage drops or the plan is upgraded
  • OpenVPN's traditional hub-and-spoke architecture routes traffic through a central server, unlike mesh VPN tools like Tailscale or NetBird that establish direct peer-to-peer connections where possible, which can add latency
  • Client configuration and certificate management for the open source version is more manual and error-prone than newer VPN tools with zero-config onboarding
  • Access Server pricing above the Growth tier reverts to custom Enterprise quoting, so very large deployments lose the pricing transparency of the lower tiers
  • The protocol's throughput is generally lower than newer kernel-integrated protocols like WireGuard under equivalent conditions, which matters for high-bandwidth use cases

PRTG Network Monitor

  • Licensing by sensor rather than device means the real cost per device is unpredictable until sensor density is measured; a small network of complex devices can need a much larger tier than device count alone suggests
  • Different PRTG licence sizes cannot be combined on one server, so outgrowing a tier means a step change to the next tier rather than a smooth incremental add
  • It requires a Windows server for on-premises deployment, which is an added infrastructure and patching burden compared with a Linux-native open source alternative
  • Pricing is materially higher than open source options like Icinga or LibreNMS for comparable core monitoring capability, and the premium is for polish and support rather than unique functionality
  • The free tier (100 sensors) is limited enough that most real deployments quickly need a paid tier, so it functions more as a trial than a genuinely usable free offering
  • Custom sensor scripting and advanced configuration still require real monitoring expertise; the polished UI does not remove the underlying complexity of correctly instrumenting a large network

Pricing, plan by plan

OpenVPN

Free
  • Access Server FreeFree
    • Up to 2 simultaneous connections
    • All features included
  • Access Server Growth$7/month
    • Per simultaneous connection beyond the free tier
    • Annual billing
  • Access Server Enterprise/IoT$undefined/month
    • Custom pricing for 2,000+ connections

PRTG Network Monitor

On request
  • PRTG 500$200/month
    • Up to 500 sensors
  • PRTG 1000$358/month
    • Up to 1,000 sensors
  • PRTG 2500$742/month
    • Up to 2,500 sensors
  • PRTG 5000$1300/month
    • Up to 5,000 sensors

Which should you pick?

Choose OpenVPN if

  • You need open source core.
  • You want to start without paying.
  • You work on Linux, Windows, macOS, iOS, Android.
  • You also want access server admin ui.
OpenVPN review

Choose PRTG Network Monitor if

  • You need sensor-based monitoring.
  • You work on Windows, Web, iOS, Android.
  • You also want auto-discovery.
PRTG Network Monitor review

Questions people ask

Is OpenVPN or PRTG Network Monitor better?
Neither clearly leads. OpenVPN starts at Free and PRTG Network Monitor at On request, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, OpenVPN or PRTG Network Monitor?
OpenVPN has a free tier; the other does not. Paid plans start at Free for OpenVPN and On request for PRTG Network Monitor.
Does OpenVPN or PRTG Network Monitor run on more platforms?
OpenVPN runs on Linux, Windows, macOS, iOS, Android. PRTG Network Monitor runs on Windows, Web, iOS, Android.
Can I use OpenVPN for free?
Yes. OpenVPN has a free tier, so you can try it without paying. PRTG Network Monitor starts at On request.
What is OpenVPN best used for?
OpenVPN is most often used for a technical team wanting a fully free, self-configured vpn server using the open source protocol without any vendor relationship, a small business wanting a supported, easier-to-administer vpn server, willing to pay per concurrent connection rather than per employee, an organisation with more staff than typical concurrent vpn usage, since access server bills only active simultaneous connections, not total accounts, an iot or large-scale deployment needing custom enterprise pricing above 2,000 connections. Of those, a technical team wanting a fully free, self-configured vpn server using the open source protocol without any vendor relationship and a small business wanting a supported, easier-to-administer vpn server, willing to pay per concurrent connection rather than per employee are not what PRTG Network Monitor is typically brought in for.
What can OpenVPN do that PRTG Network Monitor cannot?
OpenVPN covers Open source core, Access Server admin UI, Per-connection licensing, Free tier. PRTG Network Monitor covers Sensor-based monitoring, Auto-discovery, Multiple monitoring technologies, Maps and dashboards.

Answered from the vendors’ own pages

OpenVPN: Is OpenVPN free?

The open source protocol and software are free under the GPL; Access Server, the commercial packaged product, charges per simultaneous connection beyond a free 2-connection tier.

PRTG Network Monitor: Is PRTG licensed per device or per sensor?

Per sensor. Each individually monitored metric counts as one sensor, so a single device is typically several sensors.

OpenVPN: What counts as a connection for billing purposes?

A simultaneously active connected device, not a registered user account or total device count; unlimited accounts and devices can be created but only the licensed number can be connected at once.

PRTG Network Monitor: Can I combine two PRTG licence tiers on one server?

No, Paessler states different license sizes cannot be combined on one PRTG installation.

OpenVPN: How does OpenVPN compare with WireGuard-based tools like Tailscale?

OpenVPN uses a traditional hub-and-spoke VPN architecture rather than the mesh, peer-to-peer approach used by newer tools like Tailscale or NetBird.

PRTG Network Monitor: Is there a free tier?

Yes, PRTG offers a free tier limited to 100 sensors, which most production networks will exceed quickly.

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