How to Use Mastodon Federation ‘Suspend’ vs ‘Silence’ on Domain Blocks

Mastodon server administrators must decide how to handle unwanted or harmful remote domains. The two primary domain block actions are Suspend and Silence. Choosing the wrong action can either under-protect your users or over-censor legitimate content. This article explains the technical difference between Suspend and Silence and provides step-by-step instructions for applying each block type. You will learn which action to use for spam domains, defederated instances, and servers that violate your moderation policy.

What Suspend and Silence Actually Do in Mastodon Federation

Mastodon uses the ActivityPub protocol to exchange posts between servers. When you block a domain, you tell your server to stop accepting or displaying content from that instance. The Suspend action is the most severe block: your server deletes all locally cached posts from that domain, unfollows all accounts from that domain on behalf of your users, and rejects all future incoming requests. The remote server sees a permanent error when trying to deliver content to your server.

The Silence action is a softer block. Your server still accepts content from the remote domain and caches it, but that content is not visible in public timelines, hashtag pages, or explore feeds. Any post from a silenced domain automatically receives a content warning that reads “This post is from a domain you may not want to interact with.” Users can still view the post by clicking through the warning. Silence does not delete existing cached data and does not prevent users from manually following accounts on the silenced domain.

When Each Block Type Is Appropriate

Use Suspend for domains that host illegal content, mass spam, or hate speech that violates your server’s terms of service. Examples include known spam farms, instances dedicated to harassment, or servers that have been defederated by a majority of the Mastodon network. Suspend is also the correct action for domains that repeatedly attack your server with denial-of-service attempts or other technical abuse.

Use Silence for domains that are not malicious but produce content your community does not want to see in public spaces. Examples include low-quality content farms, servers with a different language that overwhelms your local timeline, or instances whose moderation policies are too lax for your server’s standards. Silence allows your users to still interact with those accounts if they choose to follow them directly.

Steps to Apply a Domain Block: Suspend or Silence

These steps assume you are an administrator of a Mastodon server. You need access to the Moderation section of your Mastodon admin panel.

1. Open the Domain Blocks page
   Log in to your Mastodon admin interface. Navigate to Moderation > Federation > Domain Blocks. This page lists all currently blocked domains and their block type.
2. Click Add new domain block
   Locate the button labeled “Add new domain block” and click it. A dialog box appears.
3. Enter the remote domain name
   Type the full domain name of the instance you want to block. For example, bad-spam-instance.com. Do not include the protocol (https://) or a trailing slash.
4. Choose the block severity: Suspend or Silence
   In the “Severity” dropdown, select either Suspend or Silence. Read the description below the dropdown to confirm your choice.
5. Optionally add a private comment
   Use the “Private comment” field to record why you blocked this domain. This note is visible only to your server’s moderators. It helps your team remember the reason for the block later.
6. Optionally add a public reason
   If you want to display a reason on the server’s about page or in federation reports, fill the “Public reason” field. This reason is visible to users on your server and to administrators of other servers.
7. Click Add domain block
   Confirm the action. Mastodon immediately applies the block. For a Suspend, the server begins deleting cached content from the blocked domain. For a Silence, the server marks all future and existing posts from that domain with a content warning.

What to Avoid When Choosing Suspend or Silence

Using Suspend When Silence Would Suffice

If you Suspend a domain that only produces mildly unwanted content, you prevent your users from following any accounts on that server. Users who previously followed accounts on the suspended domain lose those connections. The cached posts are permanently deleted. This can cause user frustration if the domain is not actually malicious.

Using Silence When Suspend Is Required

If you Silence a domain that actively spams or harasses users, the content remains on your server. Users can still see the posts by clicking the content warning. The remote server continues to send data to your server, consuming bandwidth and storage. Silence does not stop the remote server from attempting to deliver harmful content.

Forgetting to Update Block Types After a Domain Changes Behavior

A domain that was once harmless may become malicious over time. Conversely, a previously suspended domain may change ownership and moderation policies. Regularly review your domain blocks list. Change the severity from Silence to Suspend or remove the block entirely if the domain’s behavior improves.

Suspend vs Silence: Key Differences for Mastodon Domain Blocks

Item	Suspend	Silence
Effect on cached posts	Deleted immediately	Kept but hidden behind a content warning
Effect on future posts	Rejected at the server level	Accepted but hidden from public timelines
Follower connections	Unfollows all accounts from the blocked domain	Existing follows remain active
User interaction	No interaction possible	Users can interact after clicking the content warning
Bandwidth and storage impact	Stops all incoming data from the domain	Continues to accept and cache data
Recommended use case	Illegal, spam, or harassment domains	Low-quality or off-topic content domains

You can now choose the correct domain block severity for any remote instance your server encounters. If you manage a Mastodon server, open the Domain Blocks page and review your current blocks. Consider upgrading any Silence blocks to Suspend for domains that continue to cause problems. For a deeper understanding, read the Mastodon moderation documentation on the “Reject media” option, which can be combined with Silence to reduce storage usage.