A

anti-spam

Keycloak PoW Extension — adds computational PoW (proof-of-work) challenges to login, registration, and password-reset flows. Protects against bot spam and brute-force attacks by requiring clients to solve a light cryptographic puzzle before authenticating. Uses Argon2 (memory-hard, GPU-resistant) or SHA-256, with IP-adaptive difficulty that scales challenge hardness based on per-IP request patterns. Rate state is stored in Infinispan, enabling shared difficulty tracking across clustered Keycloak instances. Deploy as a standard Keycloak SPI plugin — works with any Keycloak 26.6 instance.

Three-layer defense on every submission:

Honeypot — silently rejects bots that auto-fill all form fields Solve-time validation — rejects submissions arriving faster than configured minimum (default 500ms) Hash verification — verifies proof-of-work correctness and prevents nonce replay attacks

amavis is a high-performance email content filter framework written in Perl.

A Django app that provides IP-based blocklisting via middleware. Originally developed for use on https://dpaste.com

A mail content scanner for postfix written in python

A policy daemon for postfix written in python

DomainVoider is dedicated to providing AdGuard Pro for iOS users with a custom built, privacy & security focused, simplified ad-blocking filter. Included are active malware domains from https://urlhaus.abuse.ch

https://iosprivacy.com/domainvoider

A WPezToolbox bundle of Anti-spam plugins.