diff --git a/readme.md b/readme.md
index 364bc77..21a1fce 100644
--- a/readme.md
+++ b/readme.md
@@ -271,6 +271,11 @@ There is also ```docker-prosody-module-pre-install.bash``` which downloads the s
 
 If you need additional configuration just overwrite the respective _cfg.lua_ file or add new ones.
 
+#### Firewall module
+Optionally, the Firewall module can be enabled through the ```ENABLE_FIREWALL``` environment variable. By default, the module obtains the list of spamming used known domains through the CDN service provided by [cdn.jsdelivr.net](https://cdn.jsdelivr.net/) at https://cdn.jsdelivr.net/gh/jabberspam/blacklist/blacklist.txt , but additionally a custom blacklist can be used through the ```SPAM_BLOCKLIST``` environment variable.
+
+If you need more sophisticated rules, please refer to the module [documentation](https://modules.prosody.im/mod_firewall).
+
 ### Upgrade
 
 When migrating from prosody 0.10, you need to update the database once: