Configuring vSMTP

System configuration

The behavior of the vSMTP service (network, default directories, tls, etc.) can be configured by editing the vsmtp.toml file. Its default location is /etc/vsmtp/vsmtp.toml.

When starting the vSMTP service, its configuration file is read and fully parsed. An error occurs when a key or a value is incorrect. The server never crashes if the configuration is successfully loaded.

Please refer to the vSMTP TOML key/value list chapter for further details.

Application configuration

SMTP filtering is performed by a rule engine. Scripts are written in simple, but powerful, programming language : vSMTP Scripting Language (vSL). The entry point is the main.vsl file.

Its syntax is similar to a configuration format, but with programmatic capabilities. It is based on four main concepts : rules, actions, objects and services.

Please refer to the dedicated chapter guide on vSL for further details.

Service configuration

The vsmtp.service file contains all the mandatory information to start the vSMTP service on Linux server using systemd as the system and service manager.