Also see: Denylist Management tools
Background #
Importing a shared denylist carries significant responsibilities that administrators and moderators must carefully consider. While shared denylists – whether focused on hate speech, harassment, spam, or other harms – can provide a valuable starting point for community safety, their implementation must be transparent, evidence-based, and tailored to the values and needs of the local community.
Relying on external lists without scrutiny may result in overblocking, where marginalised voices are unintentionally silenced, or underblocking, where harmful domains are not appropriately addressed due to differing safety thresholds. The core shortfall of importing a denylist lies in the potential lack of context.
Each federation decision reflects the norms, policies, and lived experiences of a specific community. Without independently reviewing the reasoning, evidence, and scope of each entry on a shared list, administrators risk inheriting decisions that may not align with their community’s trust and safety needs. Additionally, denylists maintained by external actors may not follow transparent or accountable processes.
As such, IFTAS encourages moderators to treat shared denylists as tools for guidance, and to provide accessible paths for appeal or discussion – especially when those decisions affect marginalised users or communities.
Related Reading #
- Navigating Defederation on Decentralized Social Media Platforms
- An Exploration of Decentralized Moderation on Mastodon
Domains #
The following denylist resources are for informational purposes only, and their listing here does not imply endorsement from IFTAS. IFTAS does not participate in any list creation or curation other than those listed under “IFTAS Resources”. Descriptions are sourced from the project web sites.
- Garden Fence: This list is intended as a simple starting point for Mastodon server admins who want to protect their users from the worst and most well known sources of: hate speech, racism, sexism, homophobia, transphobia Harassment, trolling, doxxing, stalking, alt-right, nazism, fascism, free-speech-as-in-bigotry, “just asking questions”, misinformation, anti-vax, conspiracy theories, sexualization of minors, potential for CSAM, spamming, denial-of-service, network disruption, abusive bots.
- FediSeer: This is a FOSS service to help Fediverse instances detect and avoid suspicious instances.
- Oliphant.Social Mastodon Blocklists: This is a place to find curated server blocklists for your own use. There are links to individual blocklist sources, as well as a custom “unified” file that takes blocklist files from other sources and merges them together into a single import file.
- Open Registration Fediverse Server Blocklist: Here you can download a CSV list of open-registration fediverse servers with more than 10,000 users. This list is automatically updated on a hourly basis.
- PeerTube Isolation List: Organizing to block Far right’s PeerTube instance from the Fediverse and isolate them
- Seirdy’s Fediverse Blocklists: Seirdy maintains four blocklists for the Fediverse.
- The Bad Space – The Bad Space arose from a need to identify instances that house bad actors, are poorly moderated, and/or contain inappropriate/offensive content (CSAM, hate speech, fascist ideology, etc.) that puts marginalized communities at risk.
- Threads Moderated Servers: Threads blocks communication with some other servers on the fediverse for a variety of reasons, including lack of Privacy Policy, violations of Community Standards or lack of compliance with deletion requests.
IFTAS Resources #
IFTAS creates original resources with no input from any of the above projects. The following resources are wholly independent and produced solely by IFTAS.
- IFTAS DNI – a curated list of the Do Not Interact domains, reviewed and labelled by IFTAS.
- IFTAS CARIAD – a domain observatory monitoring domains blocked by the largest Mastodon providers.
Domain Investigation #
Use these tools to review federating domain services.
- Defederation Investigator: Find out which Fediverse instances have blocked / defederated yours.
- FediDB: Fediverse network statistics
- fedistats: an index of nodes that have been active in the last 24 hours. You can sort by daily or weekly posts and number of active users and search node addresses.
- Fediverse Observer: Fediverse Observer finds all servers in the fediverse
IP Addresses #
- Bot IPs blocklists
- IPdeny country block downloads
- StopForumSpam – Toxic IP CIDR ranges
- Stratosphere Blocklist Generation Project
