System Requirements

Check that your server can run SpamFoo Client before you install it. This page lists the hardware, operating systems, and network access SpamFoo Client needs.

Using SmarterMail? SmarterMail downloads and runs SpamFoo Client for you, but the server still needs the hardware and network access on this page.

Hardware

Resource	Minimum	Recommended
Processor	2 cores, x64	4 or more cores, x64
Memory	1 GB free	2 GB free
Disk space	2 GB free	5 GB free
Graphics card (GPU)	(Optional) SpamFoo Client runs on the processor by default. Servers with an NVIDIA GPU can turn on GPU acceleration.

Processor SpamFoo Client requires an x64 (AMD64) processor. ARM processors are not supported.

Disk Space

Disk use grows over time. These things take up the most space:

Scan history: one record per message, kept for the Retention Period (7 days by default). Daily totals are kept for 90 days.
Stored messages: the subject and body of scanned messages, up to the Maximum Stored Messages limit.
Nightly backups: copies of the databases, 7 nights by default, on the same disk.
Log files: deleted after the Retention Period. Detailed logging and debug codes write much more.
GPU acceleration: when turned on, SpamFoo Client downloads a larger build of itself that includes NVIDIA's libraries.

The Storage card on System > Status shows the database size and where each folder is. To use less space, change these on System > Settings:

Lower Retention Period in the Scan History card.
Lower Maximum Stored Messages, or turn off Store Message Content, in the Message Content card. Without stored content, you can't read messages on the Messages page.
Lower Backups to Keep in the Database Backups card.
In the Logging card, set Log Level to Normal and clear Debug Log Codes.

The database file shrinks only when SpamFoo Client compacts it, which happens each time it starts and once a week. Restart it to free the space right away.

Supported Operating Systems

Platform	Supported Versions
Windows Server	2016, 2019, 2022, 2025
Windows	10, 11
Ubuntu	22.04 and later LTS versions
Debian	12 and later
Red Hat Enterprise Linux	8 and later
CentOS Stream	9 and later
AlmaLinux	8.10 and later
Rocky Linux	8.10 and later
Fedora	43 and later
Docker	Linux x64 hosts (see Docker)

Only versions that still get updates from their maker are supported.

Software Prerequisites

SpamFoo Client includes most of what it needs to run, including the .NET runtime.

Windows: Nothing else is needed.
Linux archive: The server needs the ICU library (libicu), which SpamFoo Client uses to read dates and text in different languages. Many servers already have it. On Red Hat, CentOS Stream, AlmaLinux, Rocky Linux, and Fedora, run sudo dnf install libicu. On Ubuntu and Debian, run sudo apt install libicu-dev.
Docker: The image already includes everything.
GPU acceleration: Also needs the NVIDIA driver.

Network Requirements

Ports

SpamFoo Client listens on port 16253 (HTTP). Your mail server sends messages to this port for scanning, and you open the admin console on it. In standalone mode you can choose another port with SPAMFOO_PORT.

Who can connect depends on how you run SpamFoo Client:

Installed on the server: Only programs on the same server can connect. If your mail server runs on another computer, set the SPAMFOO_BIND_ADDRESS environment variable. See Configure SpamFoo Client.
Docker: Other computers and containers can connect once you publish the port, such as with -p 16253:16253. The Docker example in Install SpamFoo Client publishes it only on the host's 127.0.0.1 address.

Warning Do not open port 16253 to the internet. Allow only your mail servers to reach it.

Outbound Access

SpamFoo Client needs outbound HTTPS (port 443) access to these addresses:

Address	Used For
`global-api.spamfoo.com`	Update checks, reputation data, and corrections
`downloads.spamfoo.com`	Model, program, and phishing data downloads
`developer.download.nvidia.com`	NVIDIA libraries, only when GPU acceleration is turned on

All message scanning happens on your server.

The first start needs this access to check the license and download the models.
After that, if SpamFoo Client loses access, it keeps scanning mail with the models it already has.
While access is down, models, phishing data, and reputation data are not updated.

Docker

SpamFoo Client is also available as a Docker image, spamfoo/spamfoo-client. The image includes everything SpamFoo Client needs, including the admin console and the spamfoo-client commands. Models download the first time it starts with a license key.

Requirement	Details
Host	Linux on x64
Port	16253
Storage	A volume mounted at `/data`, so settings, models, and history survive when the container is replaced

GPU acceleration is not available in the Docker image.

Mail Server Compatibility

Mail Server	How It Connects	Details
SmarterMail	Built in	Set Up SmarterMail
Other mail servers	Local HTTP API	How Integration Works

Next Steps

When your server meets these requirements, go to Install SpamFoo Client.