Rspamd

Rspamd is the new anti-spam engine of NethServer, it replaces SpamAssassin and Amavisd-new.

The official documentation of Rspamd is available at https://rspamd.com

You need to install the Email module from the Software center page. The menu where to activate it and modify its settings is on the Email > Filter page. You can read more in the Email filter section.

Rspamd Web Interface

The anti-spam component is implemented by Rspamd which provides its administrative web interface at

https://<HOST_IP>:980/rspamd

The actual URL is listed under the Applications page. By default access is granted to members of the domain admins group and to the admin user (see also Admin account). An additional special login rspamd can be used to access it. Its credentials are available from Email > Filter > Rspamd user interface (Web URL): just follow the given link.

The Rspamd web UI:

  • displays messages and actions counters,
  • shows the server configuration,
  • tracks the history of recent messages,
  • allows training the Bayes filter by submitting a message from the web form.

Status

It is the landing menu, the global statistics are available on the Rspamd service.

Troughput

The graphics are displayed in this menu to explain the activity of the anti-spam software. You can adjust the time scale (hourly, daily, weekly, montly) and modify some other settings to refine the graphics

Configuration

The Configuration > Lists menu is useful to edit lists of allowed IP/Domain/mime for the modules, you will find:

  • SURBL
  • mime list types
  • SPF_DKIM
  • DMARC
  • DKIM
  • SPF

When you want to create an exception list in a module, you could give the path /var/lib/rspamd/, the list will be editable by the Rspamd web interface.

Symbols

Rspamd use a concept of symbols which will increase or decrease the spam score when the rule has matched. The symbol weight is modifiable, negative score are for good email, positive are for spam.

Find the matching symbols

The convenient way is to use the History > History menu.

Modify a symbol weight

An easier way to change the symbol weight is to use the Rspamd WebUI: Symbols > Symbols and rules. A search box is available, you could use it to display the symbol and modify its weight.

  • Symbol score for spam is in red (positive score)
  • Symbol score for ham is in green (negative score)

If you want to remove the custom settings, you could edit the file /var/lib/rspamd/rspamd_dynamic or remove them in the Rspamd Web Interface: Configuration > Lists > rspamd_dynamic

You could redefine manually the scores defined in /etc/rspamd/scores.d/*_group.conf where they are placed by a symbol’s group. Like for the modules, you could overwrite the setting in /etc/rspamd/local.d/*_group.conf or /etc/rspamd/override.d/*_group.conf.

Priority order

scores.d/*_group.conf < local.d/*_group.conf < override.d/*_group.conf

Learning

The purpose of the Learning Menu is to train the Bayes filter, you could use directly the source of the email in the relevant text area to make learn to rspamd if the email is a spam or a ham.

Scan

The Scan menu can be used to scan directly an email and check its score and the matching symbols.

History

The Rspamd web Interface could be used to display the action done and the spam score against an email, see History > History

You could display a list of symbols by clicking on the email field, it will help you to understand the action done (reject, add_header, no_action, rewrite_subject, greylist) and gather useful informations like:

  • the sender
  • the recipient
  • the subject
  • the full score

Modules

Rspamd comes with a modular approach, all modules are not enabled by default and are customisable by the system administrator. The default settings are in the file /etc/rspamd/modules.d/MODULE_NAME.conf, relevant to the module name.

For a particular need, you can look the documentation with the list of modules.

Disable a module

You must disable a module only with a good reason. For example the ip_score module could give a high spam score due to the IP of the email sender, if it is blacklisted.

In that example we could disable the module but many modules (like ip_score) implement a white list to do not check an ip or a domain against the spam filter.

Create a file (relevant to the module name) /etc/rspamd/override.d/MODULE_NAME.conf with

enabled = false;

Restart Rspamd

systemctl restart rspamd

Modify the settings of a module

All the default settings of a module are in /etc/rspamd/modules.d/MODULE_NAME.conf, NethServer uses /etc/rspamd/local.d/MODULE_NAME.conf to modify these parameters. Therefore the prefered way is to use /etc/rspamd/override.d/MODULE_NAME.conf to either change the Rspamd and NethServer default settings. The override file uses the new parameter with a high preference, all former settings are kept.

Priority order:

modules.d/MODULE_NAME.conf < local.d/MODULE_NAME.conf < override.d/MODULE_NAME.conf

In that example we want to implement a list of IP to allow them in the ip_score module.

Create a file /etc/rspamd/override.d/ip_score.conf with

whitelist = "file:///var/lib/rspamd/ip_score_whitelist";

Restart rspamd

systemctl restart rspamd

The whitelist is editable in the rspamd UI at Configuration > Lists > ip_score_whitelist

Note

The folder /var/lib/rspamd is owned by Rspamd, all files here are modifiable by the software

Frequently asked questions

The official Rspamd FAQ could have the answer to your questions. Please see https://rspamd.com/doc/faq.html