This guide describes the main steps to get and start working with Rspamd. In particular, we describe the following setup:
Debian Jessie (or another OS with systemd)
Postfix MTA
Rmilter
Redis cache
Dovecot with Sieve plugin to sort mail and learn by moving messages to Junk folder
For those who are planning migration from SpamAssassin, it might be useful to check the SA migration guide
Preparation steps
First of all, you need a working MTA that can send and receive email for your domain using SMTP protocol. In this guide, we describe the setup of the Postfix MTA. However, Rspamd can work with other MTA software - you can find details in the integration document.
TLS Setup
It is strongly recommended to setup TLS for your mail system. We suggest to use certificates issued by Let’s Encrypt as they are free to use and are convenient to manage. To get such a certificate for your domain you need to allow Let’s Encrypt to check your domain. There are many tools available for these purposes, including the official client and couple of alternative clients, for example acmetool. The setup is fairly simple: just type
In this guide, we assume that all services have the same certificate which might not be desired if you want greater levels of security.
Postfix setup
We assume that you are installing Postfix with your OS’s package manager (e.g. apt-get install postfix). Here is the desired configuration for Postfix:
For IMAP we recommend to install Dovecot. For Debian based systems you can use the following packages:
apt-get install dovecot-imapd dovecot-sieve
Configuration of Dovecot (especially its authentication mechanisms) is a bit out of the scope for this guide but you can find many good guides at the Dovecot main site. By default, Dovecot uses Unix users in system and place mail into the standard mailbox /var/mail/username.
However, you should setup Postfix authentication. This lives in /etc/dovecot/conf.d/10-master.conf: make sure that you have uncommented the following lines in this file:
Installation of Redis is quite straightforward: install it using packages, start it with the default settings (it should listen on local interface using port 6379) and you are done. You might also want to limit memory used by Redis at some sane value:
maxmemory 500mb
maxmemory-policy volatile-lru
Note that for the moment by default stable releases of Redis listen for connections from all network interfaces. This is potentially dangerous and in most cases should be limited to the loopback interfaces, with the following configuration directive:
bind 127.0.0.1 ::1
For saving data to disk, it is also useful to setup overcommit memory behaviuor which might be useful for loaded systems. It could be done in Linux by using the following command:
When you are done with Postfix/Dovecot/Redis initial setup, it might be a good idea to setup Rmilter. Rmilter is used to connect Postfix (or Sendmail) with Rspamd. It can alter messages, change subject, reject spam, perform greylisting, check rate limits and even sign messages for authorized users/networks with DKIM signatures.
To install Rmilter, please follow the instructions on the downloads page but install rmilter package instead of rspamd. With the default configuration, Rmilter will use Redis and Rspamd on the local machine. You might want to change the bind settings as the default settings the use of unix sockets which might not work in some circumstances. To use TCP sockets for Rmilter, you can set the bind_socket option according to your Postfix setup:
bind_socket = inet:9900@127.0.0.1;
For advanced setup, please check the Rmilter documentation. Rmilter starts as daemon (e.g. by typing service rmilter start) and writes output to the system log. If you have a systemd-less system, then you can check Rmilter logs in the /var/log/mail.log file. For systemd, please check your OS documentation about reading logs as the exact command might differ from system to system.
If you use the recent Rspamd version (>= 1.4) then you should also disable Rmilter internal greylisting, ratelimit and dkim signing:
Unfortunately, these options are not in the default configuration to preserve backward compatibility with the previous versions.
Rspamd installation
The download process is described in the downloads page where you can find how to get Rspamd, how to install it in your system, and, alternatively, how to build Rspamd from the sources.
Packaging should start rspamd and configure it to run on startup on installation.
You can verify it’s running as follows:
systemctl status rspamd
Ubuntu, Debian Wheezy
To enable run on startup:
update-rc.d rspamd defaults
To start once:
/etc/init.d/rspamd start
CentOS 6
To enable run on startup:
chkconfig rspamd on
To start once:
/etc/init.d/rspamd start
Configuring Rspamd
Though Rspamd’s default config aims to be useful for most purposes you may wish to make some adjustments to suit your environment/tastes.
There are some different approaches you can take to this:
Not recommended: This will complicate upgrades: Modifying the stock config files in /etc/rspamd directly. Your package manager will not replace the modified config files on upgrade - and may prompt you to merge changes or install these files with an added extension depending on your platform.
You could create an rspamd.conf.local and/or rspamd.conf.override file in the /etc/rspamd directory. What distinguishes these is the way in which they alter the configuration - rspamd.conf.local adds or merges config elements while rspamd.conf.override adds or replaces config elements. Both affect the top-level of configuration. Objects on this level are conventionally collections ({}) - which can be merged - as can lists [], other types of settings are effectively overridden by merge operations according to their priority (site-local configuration files being higher priority than stock).
Recommended where-ever possible is use of special include files that are referenced in the stock configuration. Conventionally every configuration file in /etc/rspamd/modules.d will include two such includes:
# /etc/rspamd/modules.d/imaginary_module.conf
imaginary_module{# there would probably be some settings in this area
.include(try=true,priority=1,duplicate=merge)"$CONFDIR/local.d/imaginary_module.conf".include(try=true,priority=10)"$CONFDIR/override.d/imaginary_module.conf"}
Settings in local.d will be merged with stock configuration (where possible: ie. the setting is a list [] or collection {}) where-as settings in override.d will always replace the stock configuration. Unlike rspamd.conf.local and rspamd.conf.override, these includes are effective inside a given block of configuration ({}). Similarly to rspamd.conf.override settings in override.d have higher priority than settings generated by the web interface, unlike local.d and rspamd.conf.local.
For example, let’s change some default symbols shipped with Rspamd. To do that we can create and edit /etc/rspamd/local.d/metrics.conf:
We can also use an override file. For example, let’s redefine actions and set a more restrictive reject score. To do this, we create etc/rspamd/override.d/metrics.conf with the following content:
as this will set the other actions to be undefined. Also, you should notice that individual files are included within sections:
module { .include "..."; }
Hence, you don’t need to repeat module { ... } inside the included file.
In addition to equivalents to files in /etc/rspamd/modules.d the following includes are referenced in the stock configuration (both of local.d/override.d):
classifier-bayes.conf: included inside classifier "bayes" {} block
logging.inc: included inside logging { }
options.inc: included inside options { }
worker-normal.inc: included inside normal worker {} block
worker-controller.inc: included inside controller worker {} block
worker-proxy.inc: included inside rspamd_proxy worker {} block
Setting listening interface
Rspamd’s normal worker will, by default, listen on all interfaces on port 11333. If you’re running Rspamd on the same machine as your mailer (or whatever will be querying it) you might want to set this to ‘localhost’ instead. This option should be overridden in /etc/rspamd/local.d/worker-normal.inc:
If you plan to leave this as is you may wish to use a firewall to restrict access to your machine. Please review the worker documentation for more information about bind_socket and related settings.
Rspamd controller worker listens on the port 11334 by default, and the proxy worker uses port 11332 accordingly.
Using of Milter protocol (for Rspamd >= 1.6)
From Rspamd 1.6, rspamd proxy worker supports milter protocol which is supported by some of the popular MTA, such as Postfix or Sendmail. The introducing of this feature also finally obsoletes the Rmilter project in honor of the new integration method. Milter support is presented in rspamd_proxyonly, however, there are two possibilities to use milter protocol:
Proxy mode (for large instances) with a dedicated scan layer
Self-scan mode (for small instances)
Here, we describe the simplest self-scan option:
In this mode, rspamd_proxy scans messages itself and talk to MTA directly using Milter protocol. The advantage of this mode is its simplicity. Here is a samle configuration for this mode:
# local.d/worker-proxy.inc
milter=yes;# Enable milter mode
timeout=120s;# Needed for Milter usually
upstream"local"{default=yes;# Self-scan upstreams are always default
self_scan=yes;# Enable self-scan
}
For more advanced proxy usage, please see the corresponding documentation.
Setting the controller password
Rspamd requires a password when queried from non-trusted IPs, except for scanning messages which is unrestricted (the default config trusts the loopback interface). This is configured in the file /etc/rspamd/local.d/worker-controller.inc. The config to be modified is shown below (replace ‘q1’ with your chosen password):
Optionally you may set enable_password - if set, data-changing operations (such as Bayes training or fuzzy storage) will require this password. For example:
Important information: the default passwords (namely, q1 and q2) are BANNED, so you cannot use them in your installation. Please set the appropriate passwords before using of the controller.
Moreover, you can store an encrypted password for better security. To generate such a password just type
$ rspamadm pw
Enter passphrase:
$2$g95ywihfinjqx4r69u6mgfs9cqbfq1ay$1h4bm5uod9njfu3hdbwd3w5xf5d9u8gb7i9xnimm5u8ddq3c5byy
Then you can copy this string and store it in the configuration file. Rspamd used the PBKDF2 algorithm that makes it very hard to brute-force this password even if it has been compromised. From the version 1.3, Rspamd also supports Catena password hashing scheme which makes brute-force attacks even more memory- and computationally expensive.
For the list of all available hashing schemes, use --list option:
$ ./rspamadm pw --list
pbkdf2: PBKDF2-blake2b - standard CPU intensive "slow" KDF using blake2b hash function
catena: Catena-Butterfly - modern CPU and memory intensive KDF
Setting up the WebUI
WebUI is managed by a controller worker but you might want to proxy its requests using nginx, for example, to add TLS support. Here is a minimal setup required for nginx to do that:
worker_processes2;userwww-datawww-data;pid/var/run/nginx.pid;events{worker_connections8192;useepoll;}http{includemime.types;default_typetext/plain;sendfileon;tcp_nopushon;tcp_nodelayon;gzipon;server{listen443ssl;add_headerStrict-Transport-Security"max-age=31536000;includeSubdomains";add_headerX-Content-Type-Optionsnosniff;add_headerX-Frame-OptionsSAMEORIGIN;add_headerX-XSS-Protection"1;mode=block";includessl.conf;ssl_certificate/var/lib/acme/live/mail.example.com/fullchain;ssl_trusted_certificate/var/lib/acme/live/mail.example.com/fullchain;ssl_certificate_key/var/lib/acme/live/mail.example.com/privkey;server_nameexample.com;location/{proxy_passhttp://127.0.0.1:11334;proxy_set_headerX-Forwarded-For$proxy_add_x_forwarded_for;proxy_set_headerHost$http_host;}sslon;ssl_protocolsTLSv1.2TLSv1.1TLSv1;ssl_ciphers"EECDH+ECDSA+AESGCM:EECDH+aRSA+AESGCM:EECDH+ECDSA+SHA256:EECDH+aRSA+SHA256:EECDH+ECDSA+SHA384:EECDH+ECDSA+SHA256:EECDH+aRSA+SHA384:EDH+aRSA+AESGCM:EDH+aRSA+SHA256:EDH+aRSA:EECDH:!aNULL:!eNULL:!MEDIUM:!LOW:!3DES:!MD5:!EXP:!PSK:!SRP:!DSS:!RC4:!SEED";ssl_prefer_server_cipherson;ssl_session_cachebuiltin;ssl_session_timeout1m;ssl_staplingon;ssl_stapling_verifyon;server_tokensoff;# Do not forget to generate custom dhparam using
# openssl dhparam -out /etc/nginx/ssl/dhparam.pem 2048
ssl_dhparam/etc/nginx/dhparam.pem;ssl_ecdh_curveprime256v1;}}
You might also use subdirs, as suggested by @julienmalik:
Alternatively, you could setup HTTP authentication in nginx itself.
Setup Redis statistics
From version 1.1, it is also possible to specify Redis as a backend for statistics and caching of learned messages. Redis is recommended for clustered configurations as it allows simultaneous learning and checking and, besides, is very fast. To setup Redis, you could specify redis backend for a classifier (cache is set to the same servers accordingly).
rewrite subject - rewrite subject to *** SPAM *** original subject
reject - ultimately reject message
Each action can have its own score limit which can be modified by user settings. Rspamd assumes the following order of action scores: no action <= greylist <= add header <= rewrite subject <= reject.
Actions are NOT performed by Rspamd itself - they are just recommendations for the MTA (via Rmilter, for example) which performs the necessary actions, such as adding headers or rejecting mail.
SA spam is almost equal to Rspamd add header action in the default setup. With this action, users will be able to check for messages in their Junk or Spam folder which is usually a desired behaviour.
Scores and action settings are defined in the metric section. To override existing settings, or add scores for new symbols, you can use the rspamd.conf.local file. Here is an example of altering the reject action, changing the existing symbol and adding new symbol:
metric"default"{actions{reject=900;# Set higher reject score
}symbol"MAILLIST"{score=-4.1;# Rewrite score
}symbol"MY_SYMBOL"{score=2.1;description="My new symbol";}}
Configuring maps
Another feature of Rspamd is maps support. Maps are lists of values, for example, domain names or ip/networks listed in an external file or by HTTP that are periodically monitored by Rspamd and reloaded in case of updates. This technique is useful for writing your own rules, whitelisting or blacklisting some networks and so on. The important difference with maps is that rspamd restart is not required when those lists are changed. Maps are defined as URI strings:
http://example.com/file.map - HTTP map (server should respect If-Modified-Since header to avoid unnecessary updates)
file:///path/to/map - file map
/path/to/map - alternative syntax for file map
Within maps you can use whitespace or comments. For example, here is an example of ip/network map:
# Example map
127.0.0.1 # localhost
10.0.0.0/8
fe80::/64
There is a special module called multimap that allows you to define your own maps without writing lua rules. You can check the module’s documentation and create your configuration in rspamd.conf.override.
Configuring RBLs
Though Rspamd is free to use for any purpose many of the RBLs used in the default configuration aren’t & care should be taken to see that your use cases are not infringing. Notes about specific RBLs follow below (please follow the links for details):
Spamhaus - Commercial use forbidden (see link for definition); Limit of 300k queries or 100k SMTP connections per day
URIBL - Requires a commercial subscription if ‘excessive queries’ are sent (numbers unclear).
SURBL - Commercial use forbidden (see link for definition); Limit of 1k users or 250k queries per day
DNSWL - Commercial use forbidden (see link for definition); Limit of 100k queries per day
SpamEatingMonkey - Limit of 100k queries per day or more than 5 queries per second for more than a few minutes
SORBS - Limit of 100k users or more than 5 messages per second sustained
Mailspike - Limit of 100k messages or queries per day
UCEProtect - If you’re sending 100k queries or more per day you should use the (free) Rsync service.
Refer to the RBL and SURBL module documentation for information about disabling RBLs/SURBLs.
Using Rspamd
Using rspamc console routine
rspamc implements a feature-complete client for Rspamd. For detailed documentation refer to man rspamc.
Rspamadm is a new utility that is intended to manage rspamd directly. It comes with embedded help that can be displayed by typing:
% rspamadm help
Rspamadm 1.5.0
Usage: rspamadm [global_options] command [command_options]
Available commands:
pw Manage rspamd passwords
keypair Create encryption key pairs
configtest Perform configuration file test
fuzzy_merge Merge fuzzy databases
configdump Perform configuration file dump
control Manage rspamd main control interface
confighelp Shows help for configuration options
statconvert Convert statistics from sqlite3 to redis
fuzzyconvert Convert statistics from sqlite3 to redis
grep Search for patterns in rspamd logs
signtool Sign and verify files tool
lua Run LUA interpreter
dkim_keygen Create dkim key pairs
For example, it is possible to get help for a specific configuration option by typing something like
rspamadm confighelp -k fuzzy
See here for more information about rspamadm utilities.
Using mail system utilities
It is also useful to have a simple Sieve script to place all messages marked as spam in the Junk folder. Here is an example of such a script (~/.dovecot.sieve):
You can also setup rspamc to learn via passing messages to a certain email address. I recommend using /etc/aliases for these purposes and mail-redirect command (e.g. provided by Mail Redirect addon for Thunderbird MUA). The desired aliases could be the following:
You’d need some less predictable aliases to avoid sending messages to such addresses by some adversary or just by a mistake to prevent statistics pollution.
There is also an add-on for Thunderbird MUA written by Alexander Moisseev to visualise Rspamd stats. You can download it from its homepage. You’d need to add extended spam headers (X-Spamd-Result) with Rmilter and/or (from add-on’s version 0.8.0) X-Spam-Score and X-Spam-Report headers with Exim to make the whole setup work.
To enable extended spam headers in Rmilter add the following line to rmilter.conf:
spamd{...extended_spam_headers=yes;}
To enable headers in Exim refer to the “Integration with Exim MTA” section of the MTA integration document.
Here is a screenshot of this addon in use:
Using the WebUI
Rspamd has a built-in WebUI which supports setting metric actions and scores; Bayes training and scanning messages - for more information see the WebUI documentation.
