diff --git a/app/controllers/admin/domain_blocks_controller.rb b/app/controllers/admin/domain_blocks_controller.rb
index 081550b762..b9691c5a3a 100644
--- a/app/controllers/admin/domain_blocks_controller.rb
+++ b/app/controllers/admin/domain_blocks_controller.rb
@@ -31,31 +31,41 @@ module Admin
       @domain_block = DomainBlock.new(resource_params)
       existing_domain_block = resource_params[:domain].present? ? DomainBlock.rule_for(resource_params[:domain]) : nil
 
+      # Disallow accidentally downgrading a domain block
       if existing_domain_block.present? && !@domain_block.stricter_than?(existing_domain_block)
         @domain_block.save
         flash.now[:alert] = I18n.t('admin.domain_blocks.existing_domain_block_html', name: existing_domain_block.domain, unblock_url: admin_domain_block_path(existing_domain_block)).html_safe
         @domain_block.errors.delete(:domain)
-        render :new
-      else
-        if existing_domain_block.present?
-          @domain_block = existing_domain_block
-          @domain_block.update(resource_params)
-        end
+        return render :new
+      end
 
-        if @domain_block.save
-          DomainBlockWorker.perform_async(@domain_block.id)
-          log_action :create, @domain_block
-          redirect_to admin_instances_path(limited: '1'), notice: I18n.t('admin.domain_blocks.created_msg')
-        else
-          render :new
-        end
+      # Allow transparently upgrading a domain block
+      if existing_domain_block.present?
+        @domain_block = existing_domain_block
+        @domain_block.assign_attributes(resource_params)
+      end
+
+      # Require explicit confirmation when suspending
+      return render :confirm_suspension if requires_confirmation?
+
+      if @domain_block.save
+        DomainBlockWorker.perform_async(@domain_block.id)
+        log_action :create, @domain_block
+        redirect_to admin_instances_path(limited: '1'), notice: I18n.t('admin.domain_blocks.created_msg')
+      else
+        render :new
       end
     end
 
     def update
       authorize :domain_block, :update?
 
-      if @domain_block.update(update_params)
+      @domain_block.assign_attributes(update_params)
+
+      # Require explicit confirmation when suspending
+      return render :confirm_suspension if requires_confirmation?
+
+      if @domain_block.save
         DomainBlockWorker.perform_async(@domain_block.id, @domain_block.severity_previously_changed?)
         log_action :update, @domain_block
         redirect_to admin_instances_path(limited: '1'), notice: I18n.t('admin.domain_blocks.created_msg')
@@ -92,5 +102,9 @@ module Admin
     def action_from_button
       'save' if params[:save]
     end
+
+    def requires_confirmation?
+      @domain_block.valid? && (@domain_block.new_record? || @domain_block.severity_changed?) && @domain_block.severity.to_s == 'suspend' && !params[:confirm]
+    end
   end
 end
diff --git a/app/javascript/mastodon/components/admin/ImpactReport.jsx b/app/javascript/mastodon/components/admin/ImpactReport.jsx
new file mode 100644
index 0000000000..c27ee0ab08
--- /dev/null
+++ b/app/javascript/mastodon/components/admin/ImpactReport.jsx
@@ -0,0 +1,91 @@
+import PropTypes from 'prop-types';
+import { PureComponent } from 'react';
+
+import { FormattedNumber, FormattedMessage } from 'react-intl';
+
+import classNames from 'classnames';
+
+import api from 'mastodon/api';
+import { Skeleton } from 'mastodon/components/skeleton';
+
+export default class ImpactReport extends PureComponent {
+
+  static propTypes = {
+    domain: PropTypes.string.isRequired,
+  };
+
+  state = {
+    loading: true,
+    data: null,
+  };
+
+  componentDidMount () {
+    const { domain } = this.props;
+
+    const params = {
+      domain: domain,
+      include_subdomains: true,
+    };
+
+    api().post('/api/v1/admin/measures', {
+      keys: ['instance_accounts', 'instance_follows', 'instance_followers'],
+      start_at: null,
+      end_at: null,
+      instance_accounts: params,
+      instance_follows: params,
+      instance_followers: params,
+    }).then(res => {
+      this.setState({
+        loading: false,
+        data: res.data,
+      });
+    }).catch(err => {
+      console.error(err);
+    });
+  }
+
+  render () {
+    const { loading, data } = this.state;
+
+    return (
+      <div className='dimension'>
+        <h4><FormattedMessage id='admin.impact_report.title' defaultMessage='Impact summary' /></h4>
+
+        <table>
+          <tbody>
+            <tr className='dimension__item'>
+              <td className='dimension__item__key'>
+                <FormattedMessage id='admin.impact_report.instance_accounts' defaultMessage='Accounts profiles this would delete' />
+              </td>
+
+              <td className='dimension__item__value'>
+                {loading ? <Skeleton width={60} /> : <FormattedNumber value={data[0].total} />}
+              </td>
+            </tr>
+
+            <tr className={classNames('dimension__item', { negative: !loading && data[1].total > 0 })}>
+              <td className='dimension__item__key'>
+                <FormattedMessage id='admin.impact_report.instance_follows' defaultMessage='Followers their users would lose' />
+              </td>
+
+              <td className='dimension__item__value'>
+                {loading ? <Skeleton width={60} /> : <FormattedNumber value={data[1].total} />}
+              </td>
+            </tr>
+
+            <tr className={classNames('dimension__item', { negative: !loading && data[2].total > 0 })}>
+              <td className='dimension__item__key'>
+                <FormattedMessage id='admin.impact_report.instance_followers' defaultMessage='Followers our users would lose' />
+              </td>
+
+              <td className='dimension__item__value'>
+                {loading ? <Skeleton width={60} /> : <FormattedNumber value={data[2].total} />}
+              </td>
+            </tr>
+          </tbody>
+        </table>
+      </div>
+    );
+  }
+
+}
diff --git a/app/javascript/mastodon/locales/en.json b/app/javascript/mastodon/locales/en.json
index a9c9f534f6..5ed793cdba 100644
--- a/app/javascript/mastodon/locales/en.json
+++ b/app/javascript/mastodon/locales/en.json
@@ -73,6 +73,10 @@
   "admin.dashboard.retention.average": "Average",
   "admin.dashboard.retention.cohort": "Sign-up month",
   "admin.dashboard.retention.cohort_size": "New users",
+  "admin.impact_report.instance_accounts": "Accounts profiles this would delete",
+  "admin.impact_report.instance_followers": "Followers our users would lose",
+  "admin.impact_report.instance_follows": "Followers their users would lose",
+  "admin.impact_report.title": "Impact summary",
   "alert.rate_limited.message": "Please retry after {retry_time, time, medium}.",
   "alert.rate_limited.title": "Rate limited",
   "alert.unexpected.message": "An unexpected error occurred.",
diff --git a/app/javascript/styles/mastodon/admin.scss b/app/javascript/styles/mastodon/admin.scss
index a439b0e392..f4dfe55607 100644
--- a/app/javascript/styles/mastodon/admin.scss
+++ b/app/javascript/styles/mastodon/admin.scss
@@ -1309,6 +1309,15 @@ a.sparkline {
     &:last-child {
       border-bottom: 0;
     }
+
+    &.negative {
+      color: $error-value-color;
+      font-weight: 700;
+
+      .dimension__item__value {
+        color: $error-value-color;
+      }
+    }
   }
 }
 
diff --git a/app/lib/admin/metrics/measure/instance_accounts_measure.rb b/app/lib/admin/metrics/measure/instance_accounts_measure.rb
index 4c61a064a8..14a61de88c 100644
--- a/app/lib/admin/metrics/measure/instance_accounts_measure.rb
+++ b/app/lib/admin/metrics/measure/instance_accounts_measure.rb
@@ -16,7 +16,9 @@ class Admin::Metrics::Measure::InstanceAccountsMeasure < Admin::Metrics::Measure
   protected
 
   def perform_total_query
-    Account.where(domain: params[:domain]).count
+    domain = params[:domain]
+    domain = Instance.by_domain_and_subdomains(params[:domain]).select(:domain) if params[:include_subdomains]
+    Account.where(domain: domain).count
   end
 
   def perform_previous_total_query
@@ -24,13 +26,21 @@ class Admin::Metrics::Measure::InstanceAccountsMeasure < Admin::Metrics::Measure
   end
 
   def perform_data_query
+    account_matching_sql = begin
+      if params[:include_subdomains]
+        "accounts.domain IN (SELECT domain FROM instances WHERE reverse('.' || domain) LIKE reverse('.' || $3::text))"
+      else
+        'accounts.domain = $3::text'
+      end
+    end
+
     sql = <<-SQL.squish
       SELECT axis.*, (
         WITH new_accounts AS (
           SELECT accounts.id
           FROM accounts
           WHERE date_trunc('day', accounts.created_at)::date = axis.period
-            AND accounts.domain = $3::text
+            AND #{account_matching_sql}
         )
         SELECT count(*) FROM new_accounts
       ) AS value
@@ -53,6 +63,6 @@ class Admin::Metrics::Measure::InstanceAccountsMeasure < Admin::Metrics::Measure
   end
 
   def params
-    @params.permit(:domain)
+    @params.permit(:domain, :include_subdomains)
   end
 end
diff --git a/app/lib/admin/metrics/measure/instance_followers_measure.rb b/app/lib/admin/metrics/measure/instance_followers_measure.rb
index caa60013b2..dc0f5492c9 100644
--- a/app/lib/admin/metrics/measure/instance_followers_measure.rb
+++ b/app/lib/admin/metrics/measure/instance_followers_measure.rb
@@ -16,7 +16,9 @@ class Admin::Metrics::Measure::InstanceFollowersMeasure < Admin::Metrics::Measur
   protected
 
   def perform_total_query
-    Follow.joins(:account).merge(Account.where(domain: params[:domain])).count
+    domain = params[:domain]
+    domain = Instance.by_domain_and_subdomains(params[:domain]).select(:domain) if params[:include_subdomains]
+    Follow.joins(:account).merge(Account.where(domain: domain)).count
   end
 
   def perform_previous_total_query
@@ -24,6 +26,14 @@ class Admin::Metrics::Measure::InstanceFollowersMeasure < Admin::Metrics::Measur
   end
 
   def perform_data_query
+    account_matching_sql = begin
+      if params[:include_subdomains]
+        "accounts.domain IN (SELECT domain FROM instances WHERE reverse('.' || domain) LIKE reverse('.' || $3::text))"
+      else
+        'accounts.domain = $3::text'
+      end
+    end
+
     sql = <<-SQL.squish
       SELECT axis.*, (
         WITH new_followers AS (
@@ -31,7 +41,7 @@ class Admin::Metrics::Measure::InstanceFollowersMeasure < Admin::Metrics::Measur
           FROM follows
           INNER JOIN accounts ON follows.account_id = accounts.id
           WHERE date_trunc('day', follows.created_at)::date = axis.period
-            AND accounts.domain = $3::text
+            AND #{account_matching_sql}
         )
         SELECT count(*) FROM new_followers
       ) AS value
@@ -54,6 +64,6 @@ class Admin::Metrics::Measure::InstanceFollowersMeasure < Admin::Metrics::Measur
   end
 
   def params
-    @params.permit(:domain)
+    @params.permit(:domain, :include_subdomains)
   end
 end
diff --git a/app/lib/admin/metrics/measure/instance_follows_measure.rb b/app/lib/admin/metrics/measure/instance_follows_measure.rb
index b026c7e6d0..f2088ffb30 100644
--- a/app/lib/admin/metrics/measure/instance_follows_measure.rb
+++ b/app/lib/admin/metrics/measure/instance_follows_measure.rb
@@ -16,7 +16,9 @@ class Admin::Metrics::Measure::InstanceFollowsMeasure < Admin::Metrics::Measure:
   protected
 
   def perform_total_query
-    Follow.joins(:target_account).merge(Account.where(domain: params[:domain])).count
+    domain = params[:domain]
+    domain = Instance.by_domain_and_subdomains(params[:domain]).select(:domain) if params[:include_subdomains]
+    Follow.joins(:target_account).merge(Account.where(domain: domain)).count
   end
 
   def perform_previous_total_query
@@ -24,6 +26,14 @@ class Admin::Metrics::Measure::InstanceFollowsMeasure < Admin::Metrics::Measure:
   end
 
   def perform_data_query
+    account_matching_sql = begin
+      if params[:include_subdomains]
+        "accounts.domain IN (SELECT domain FROM instances WHERE reverse('.' || domain) LIKE reverse('.' || $3::text))"
+      else
+        'accounts.domain = $3::text'
+      end
+    end
+
     sql = <<-SQL.squish
       SELECT axis.*, (
         WITH new_follows AS (
@@ -31,7 +41,7 @@ class Admin::Metrics::Measure::InstanceFollowsMeasure < Admin::Metrics::Measure:
           FROM follows
           INNER JOIN accounts ON follows.target_account_id = accounts.id
           WHERE date_trunc('day', follows.created_at)::date = axis.period
-            AND accounts.domain = $3::text
+            AND #{account_matching_sql}
         )
         SELECT count(*) FROM new_follows
       ) AS value
@@ -54,6 +64,6 @@ class Admin::Metrics::Measure::InstanceFollowsMeasure < Admin::Metrics::Measure:
   end
 
   def params
-    @params.permit(:domain)
+    @params.permit(:domain, :include_subdomains)
   end
 end
diff --git a/app/lib/admin/metrics/measure/instance_media_attachments_measure.rb b/app/lib/admin/metrics/measure/instance_media_attachments_measure.rb
index 2e2154c92b..779883e031 100644
--- a/app/lib/admin/metrics/measure/instance_media_attachments_measure.rb
+++ b/app/lib/admin/metrics/measure/instance_media_attachments_measure.rb
@@ -26,7 +26,9 @@ class Admin::Metrics::Measure::InstanceMediaAttachmentsMeasure < Admin::Metrics:
   protected
 
   def perform_total_query
-    MediaAttachment.joins(:account).merge(Account.where(domain: params[:domain])).sum('COALESCE(file_file_size, 0) + COALESCE(thumbnail_file_size, 0)')
+    domain = params[:domain]
+    domain = Instance.by_domain_and_subdomains(params[:domain]).select(:domain) if params[:include_subdomains]
+    MediaAttachment.joins(:account).merge(Account.where(domain: domain)).sum('COALESCE(file_file_size, 0) + COALESCE(thumbnail_file_size, 0)')
   end
 
   def perform_previous_total_query
@@ -34,6 +36,14 @@ class Admin::Metrics::Measure::InstanceMediaAttachmentsMeasure < Admin::Metrics:
   end
 
   def perform_data_query
+    account_matching_sql = begin
+      if params[:include_subdomains]
+        "accounts.domain IN (SELECT domain FROM instances WHERE reverse('.' || domain) LIKE reverse('.' || $3::text))"
+      else
+        'accounts.domain = $3::text'
+      end
+    end
+
     sql = <<-SQL.squish
       SELECT axis.*, (
         WITH new_media_attachments AS (
@@ -41,7 +51,7 @@ class Admin::Metrics::Measure::InstanceMediaAttachmentsMeasure < Admin::Metrics:
           FROM media_attachments
           INNER JOIN accounts ON accounts.id = media_attachments.account_id
           WHERE date_trunc('day', media_attachments.created_at)::date = axis.period
-            AND accounts.domain = $3::text
+            AND #{account_matching_sql}
         )
         SELECT SUM(size) FROM new_media_attachments
       ) AS value
@@ -64,6 +74,6 @@ class Admin::Metrics::Measure::InstanceMediaAttachmentsMeasure < Admin::Metrics:
   end
 
   def params
-    @params.permit(:domain)
+    @params.permit(:domain, :include_subdomains)
   end
 end
diff --git a/app/lib/admin/metrics/measure/instance_reports_measure.rb b/app/lib/admin/metrics/measure/instance_reports_measure.rb
index 6b3f350674..c1f7189bfe 100644
--- a/app/lib/admin/metrics/measure/instance_reports_measure.rb
+++ b/app/lib/admin/metrics/measure/instance_reports_measure.rb
@@ -16,7 +16,9 @@ class Admin::Metrics::Measure::InstanceReportsMeasure < Admin::Metrics::Measure:
   protected
 
   def perform_total_query
-    Report.where(target_account: Account.where(domain: params[:domain])).count
+    domain = params[:domain]
+    domain = Instance.by_domain_and_subdomains(params[:domain]).select(:domain) if params[:include_subdomains]
+    Report.where(target_account: Account.where(domain: domain)).count
   end
 
   def perform_previous_total_query
@@ -24,6 +26,14 @@ class Admin::Metrics::Measure::InstanceReportsMeasure < Admin::Metrics::Measure:
   end
 
   def perform_data_query
+    account_matching_sql = begin
+      if params[:include_subdomains]
+        "accounts.domain IN (SELECT domain FROM instances WHERE reverse('.' || domain) LIKE reverse('.' || $3::text))"
+      else
+        'accounts.domain = $3::text'
+      end
+    end
+
     sql = <<-SQL.squish
       SELECT axis.*, (
         WITH new_reports AS (
@@ -31,7 +41,7 @@ class Admin::Metrics::Measure::InstanceReportsMeasure < Admin::Metrics::Measure:
           FROM reports
           INNER JOIN accounts ON accounts.id = reports.target_account_id
           WHERE date_trunc('day', reports.created_at)::date = axis.period
-            AND accounts.domain = $3::text
+            AND #{account_matching_sql}
         )
         SELECT count(*) FROM new_reports
       ) AS value
@@ -54,6 +64,6 @@ class Admin::Metrics::Measure::InstanceReportsMeasure < Admin::Metrics::Measure:
   end
 
   def params
-    @params.permit(:domain)
+    @params.permit(:domain, :include_subdomains)
   end
 end
diff --git a/app/lib/admin/metrics/measure/instance_statuses_measure.rb b/app/lib/admin/metrics/measure/instance_statuses_measure.rb
index 86b10da6c4..1b38b40c55 100644
--- a/app/lib/admin/metrics/measure/instance_statuses_measure.rb
+++ b/app/lib/admin/metrics/measure/instance_statuses_measure.rb
@@ -16,7 +16,9 @@ class Admin::Metrics::Measure::InstanceStatusesMeasure < Admin::Metrics::Measure
   protected
 
   def perform_total_query
-    Status.joins(:account).merge(Account.where(domain: params[:domain])).count
+    domain = params[:domain]
+    domain = Instance.by_domain_and_subdomains(params[:domain]).select(:domain) if params[:include_subdomains]
+    Status.joins(:account).merge(Account.where(domain: domain)).count
   end
 
   def perform_previous_total_query
@@ -24,6 +26,14 @@ class Admin::Metrics::Measure::InstanceStatusesMeasure < Admin::Metrics::Measure
   end
 
   def perform_data_query
+    account_matching_sql = begin
+      if params[:include_subdomains]
+        "accounts.domain IN (SELECT domain FROM instances WHERE reverse('.' || domain) LIKE reverse('.' || $5::text))"
+      else
+        'accounts.domain = $5::text'
+      end
+    end
+
     sql = <<-SQL.squish
       SELECT axis.*, (
         WITH new_statuses AS (
@@ -31,7 +41,7 @@ class Admin::Metrics::Measure::InstanceStatusesMeasure < Admin::Metrics::Measure
           FROM statuses
           INNER JOIN accounts ON accounts.id = statuses.account_id
           WHERE statuses.id BETWEEN $3 AND $4
-            AND accounts.domain = $5::text
+            AND #{account_matching_sql}
             AND date_trunc('day', statuses.created_at)::date = axis.period
         )
         SELECT count(*) FROM new_statuses
@@ -55,6 +65,6 @@ class Admin::Metrics::Measure::InstanceStatusesMeasure < Admin::Metrics::Measure
   end
 
   def params
-    @params.permit(:domain)
+    @params.permit(:domain, :include_subdomains)
   end
 end
diff --git a/app/views/admin/domain_blocks/confirm_suspension.html.haml b/app/views/admin/domain_blocks/confirm_suspension.html.haml
new file mode 100644
index 0000000000..e291d4ce22
--- /dev/null
+++ b/app/views/admin/domain_blocks/confirm_suspension.html.haml
@@ -0,0 +1,22 @@
+- content_for :page_title do
+  = t('.title', domain: Addressable::IDNA.to_unicode(@domain_block.domain))
+
+= simple_form_for @domain_block, url: admin_domain_blocks_path(@domain_block) do |f|
+
+  %p.hint= t('.preamble_html', domain: Addressable::IDNA.to_unicode(@domain_block.domain))
+  %ul.hint
+    %li= t('.stop_communication')
+    %li= t('.remove_all_data')
+    %li= t('.undo_relationships')
+    %li.negative-hint= t('.permanent_action')
+
+  - %i(domain severity reject_media reject_reports obfuscate private_comment public_comment).each do |key|
+    = f.hidden_field key
+
+  %hr.spacer
+
+  = react_admin_component :impact_report, domain: @domain_block.domain
+
+  .actions
+    = link_to t('.cancel'), admin_instances_path, class: 'button button-tertiary'
+    = f.button :submit, t('.confirm'), class: 'button negative', name: :confirm
diff --git a/config/locales/en.yml b/config/locales/en.yml
index 76198763a4..6a8da6e60d 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -382,6 +382,15 @@ en:
       undo: Disallow federation with domain
     domain_blocks:
       add_new: Add new domain block
+      confirm_suspension:
+        cancel: Cancel
+        confirm: Suspend
+        permanent_action: Undoing the suspension will not restore any data or relationship.
+        preamble_html: You are about to suspend <strong>%{domain}</strong> and its subdomains.
+        remove_all_data: This will remove all content, media, and profile data for this domain's accounts from your server.
+        stop_communication: Your server will stop communicating with these servers.
+        title: Confirm domain block for %{domain}
+        undo_relationships: This will undo any follow relationship between accounts of these servers and yours.
       created_msg: Domain block is now being processed
       destroyed_msg: Domain block has been undone
       domain: Domain
diff --git a/spec/controllers/admin/domain_blocks_controller_spec.rb b/spec/controllers/admin/domain_blocks_controller_spec.rb
index 6aed172ac5..d499aa64ce 100644
--- a/spec/controllers/admin/domain_blocks_controller_spec.rb
+++ b/spec/controllers/admin/domain_blocks_controller_spec.rb
@@ -40,42 +40,135 @@ RSpec.describe Admin::DomainBlocksController do
   end
 
   describe 'POST #create' do
-    it 'blocks the domain when succeeded to save' do
+    before do
       allow(DomainBlockWorker).to receive(:perform_async).and_return(true)
-
-      post :create, params: { domain_block: { domain: 'example.com', severity: 'silence' } }
-
-      expect(DomainBlockWorker).to have_received(:perform_async)
-      expect(flash[:notice]).to eq I18n.t('admin.domain_blocks.created_msg')
-      expect(response).to redirect_to(admin_instances_path(limited: '1'))
     end
 
-    it 'renders new when failed to save' do
-      Fabricate(:domain_block, domain: 'example.com', severity: 'suspend')
-      allow(DomainBlockWorker).to receive(:perform_async).and_return(true)
+    context 'with "silence" severity and no conflict' do
+      before do
+        post :create, params: { domain_block: { domain: 'example.com', severity: 'silence' } }
+      end
 
-      post :create, params: { domain_block: { domain: 'example.com', severity: 'silence' } }
+      it 'records a block' do
+        expect(DomainBlock.exists?(domain: 'example.com', severity: 'silence')).to be true
+      end
 
-      expect(DomainBlockWorker).to_not have_received(:perform_async)
-      expect(response).to render_template :new
+      it 'calls DomainBlockWorker' do
+        expect(DomainBlockWorker).to have_received(:perform_async)
+      end
+
+      it 'redirects with a success message' do
+        expect(flash[:notice]).to eq I18n.t('admin.domain_blocks.created_msg')
+        expect(response).to redirect_to(admin_instances_path(limited: '1'))
+      end
     end
 
-    it 'allows upgrading a block' do
-      Fabricate(:domain_block, domain: 'example.com', severity: 'silence')
-      allow(DomainBlockWorker).to receive(:perform_async).and_return(true)
+    context 'when the new domain block conflicts with an existing one' do
+      before do
+        Fabricate(:domain_block, domain: 'example.com', severity: 'suspend')
+        post :create, params: { domain_block: { domain: 'example.com', severity: 'silence' } }
+      end
 
-      post :create, params: { domain_block: { domain: 'example.com', severity: 'silence', reject_media: true, reject_reports: true } }
+      it 'does not record a block' do
+        expect(DomainBlock.exists?(domain: 'example.com', severity: 'silence')).to be false
+      end
 
-      expect(DomainBlockWorker).to have_received(:perform_async)
-      expect(flash[:notice]).to eq I18n.t('admin.domain_blocks.created_msg')
-      expect(response).to redirect_to(admin_instances_path(limited: '1'))
+      it 'does not call DomainBlockWorker' do
+        expect(DomainBlockWorker).to_not have_received(:perform_async)
+      end
+
+      it 'renders new' do
+        expect(response).to render_template :new
+      end
+    end
+
+    context 'with "suspend" severity and no conflict' do
+      context 'without a confirmation' do
+        before do
+          post :create, params: { domain_block: { domain: 'example.com', severity: 'suspend', reject_media: true, reject_reports: true } }
+        end
+
+        it 'does not record a block' do
+          expect(DomainBlock.exists?(domain: 'example.com', severity: 'suspend')).to be false
+        end
+
+        it 'does not call DomainBlockWorker' do
+          expect(DomainBlockWorker).to_not have_received(:perform_async)
+        end
+
+        it 'renders confirm_suspension' do
+          expect(response).to render_template :confirm_suspension
+        end
+      end
+
+      context 'with a confirmation' do
+        before do
+          post :create, params: { :domain_block => { domain: 'example.com', severity: 'suspend', reject_media: true, reject_reports: true }, 'confirm' => '' }
+        end
+
+        it 'records a block' do
+          expect(DomainBlock.exists?(domain: 'example.com', severity: 'suspend')).to be true
+        end
+
+        it 'calls DomainBlockWorker' do
+          expect(DomainBlockWorker).to have_received(:perform_async)
+        end
+
+        it 'redirects with a success message' do
+          expect(flash[:notice]).to eq I18n.t('admin.domain_blocks.created_msg')
+          expect(response).to redirect_to(admin_instances_path(limited: '1'))
+        end
+      end
+    end
+
+    context 'when upgrading an existing block' do
+      before do
+        Fabricate(:domain_block, domain: 'example.com', severity: 'silence')
+      end
+
+      context 'without a confirmation' do
+        before do
+          post :create, params: { domain_block: { domain: 'example.com', severity: 'suspend', reject_media: true, reject_reports: true } }
+        end
+
+        it 'does not record a block' do
+          expect(DomainBlock.exists?(domain: 'example.com', severity: 'suspend')).to be false
+        end
+
+        it 'does not call DomainBlockWorker' do
+          expect(DomainBlockWorker).to_not have_received(:perform_async)
+        end
+
+        it 'renders confirm_suspension' do
+          expect(response).to render_template :confirm_suspension
+        end
+      end
+
+      context 'with a confirmation' do
+        before do
+          post :create, params: { :domain_block => { domain: 'example.com', severity: 'suspend', reject_media: true, reject_reports: true }, 'confirm' => '' }
+        end
+
+        it 'updates the record' do
+          expect(DomainBlock.exists?(domain: 'example.com', severity: 'suspend')).to be true
+        end
+
+        it 'calls DomainBlockWorker' do
+          expect(DomainBlockWorker).to have_received(:perform_async)
+        end
+
+        it 'redirects with a success message' do
+          expect(flash[:notice]).to eq I18n.t('admin.domain_blocks.created_msg')
+          expect(response).to redirect_to(admin_instances_path(limited: '1'))
+        end
+      end
     end
   end
 
   describe 'PUT #update' do
     let!(:remote_account) { Fabricate(:account, domain: 'example.com') }
     let(:subject) do
-      post :update, params: { id: domain_block.id, domain_block: { domain: 'example.com', severity: new_severity } }
+      post :update, params: { :id => domain_block.id, :domain_block => { domain: 'example.com', severity: new_severity }, 'confirm' => '' }
     end
     let(:domain_block) { Fabricate(:domain_block, domain: 'example.com', severity: original_severity) }
 
diff --git a/spec/features/admin/domain_blocks_spec.rb b/spec/features/admin/domain_blocks_spec.rb
new file mode 100644
index 0000000000..3cf60a48ae
--- /dev/null
+++ b/spec/features/admin/domain_blocks_spec.rb
@@ -0,0 +1,78 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+describe 'blocking domains through the moderation interface' do
+  before do
+    sign_in Fabricate(:user, role: UserRole.find_by(name: 'Admin')), scope: :user
+  end
+
+  context 'when silencing a new domain' do
+    it 'adds a new domain block' do
+      visit new_admin_domain_block_path
+
+      fill_in 'domain_block_domain', with: 'example.com'
+      select I18n.t('admin.domain_blocks.new.severity.silence'), from: 'domain_block_severity'
+      click_on I18n.t('admin.domain_blocks.new.create')
+
+      expect(DomainBlock.exists?(domain: 'example.com', severity: 'silence')).to be true
+    end
+  end
+
+  context 'when suspending a new domain' do
+    it 'presents a confirmation screen before suspending the domain' do
+      visit new_admin_domain_block_path
+
+      fill_in 'domain_block_domain', with: 'example.com'
+      select I18n.t('admin.domain_blocks.new.severity.suspend'), from: 'domain_block_severity'
+      click_on I18n.t('admin.domain_blocks.new.create')
+
+      # It presents a confirmation screen
+      expect(page).to have_title(I18n.t('admin.domain_blocks.confirm_suspension.title', domain: 'example.com'))
+
+      # Confirming creates a block
+      click_on I18n.t('admin.domain_blocks.confirm_suspension.confirm')
+
+      expect(DomainBlock.exists?(domain: 'example.com', severity: 'suspend')).to be true
+    end
+  end
+
+  context 'when suspending a domain that is already silenced' do
+    it 'presents a confirmation screen before suspending the domain' do
+      domain_block = Fabricate(:domain_block, domain: 'example.com', severity: 'silence')
+
+      visit new_admin_domain_block_path
+
+      fill_in 'domain_block_domain', with: 'example.com'
+      select I18n.t('admin.domain_blocks.new.severity.suspend'), from: 'domain_block_severity'
+      click_on I18n.t('admin.domain_blocks.new.create')
+
+      # It presents a confirmation screen
+      expect(page).to have_title(I18n.t('admin.domain_blocks.confirm_suspension.title', domain: 'example.com'))
+
+      # Confirming updates the block
+      click_on I18n.t('admin.domain_blocks.confirm_suspension.confirm')
+
+      expect(domain_block.reload.severity).to eq 'silence'
+    end
+  end
+
+  context 'when editing a domain block' do
+    it 'presents a confirmation screen before suspending the domain' do
+      domain_block = Fabricate(:domain_block, domain: 'example.com', severity: 'silence')
+
+      visit edit_admin_domain_block_path(domain_block)
+
+      select I18n.t('admin.domain_blocks.new.severity.suspend'), from: 'domain_block_severity'
+      click_on I18n.t('generic.save_changes')
+
+      # It presents a confirmation screen
+      expect(page).to have_title(I18n.t('admin.domain_blocks.confirm_suspension.title', domain: 'example.com'))
+
+      # Confirming updates the block
+      click_on I18n.t('admin.domain_blocks.confirm_suspension.confirm')
+
+      expect(domain_block.reload.severity).to eq 'silence'
+    end
+  end
+end
diff --git a/spec/lib/admin/metrics/measure/instance_accounts_measure_spec.rb b/spec/lib/admin/metrics/measure/instance_accounts_measure_spec.rb
new file mode 100644
index 0000000000..29a157491e
--- /dev/null
+++ b/spec/lib/admin/metrics/measure/instance_accounts_measure_spec.rb
@@ -0,0 +1,40 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+describe Admin::Metrics::Measure::InstanceAccountsMeasure do
+  subject(:measure) { described_class.new(start_at, end_at, params) }
+
+  let(:domain) { 'example.com' }
+
+  let(:start_at) { 2.days.ago }
+  let(:end_at)   { Time.now.utc }
+
+  let(:params) { ActionController::Parameters.new(domain: domain) }
+
+  before do
+    Fabricate(:account, domain: domain, created_at: 1.year.ago)
+    Fabricate(:account, domain: domain, created_at: 1.month.ago)
+    Fabricate(:account, domain: domain)
+
+    Fabricate(:account, domain: "foo.#{domain}", created_at: 1.year.ago)
+    Fabricate(:account, domain: "foo.#{domain}")
+    Fabricate(:account, domain: "bar.#{domain}")
+  end
+
+  describe 'total' do
+    context 'without include_subdomains' do
+      it 'returns the expected number of accounts' do
+        expect(measure.total).to eq 3
+      end
+    end
+
+    context 'with include_subdomains' do
+      let(:params) { ActionController::Parameters.new(domain: domain, include_subdomains: 'true') }
+
+      it 'returns the expected number of accounts' do
+        expect(measure.total).to eq 6
+      end
+    end
+  end
+end
diff --git a/spec/lib/admin/metrics/measure/instance_followers_measure_spec.rb b/spec/lib/admin/metrics/measure/instance_followers_measure_spec.rb
new file mode 100644
index 0000000000..ebf789c1b3
--- /dev/null
+++ b/spec/lib/admin/metrics/measure/instance_followers_measure_spec.rb
@@ -0,0 +1,42 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+describe Admin::Metrics::Measure::InstanceFollowersMeasure do
+  subject(:measure) { described_class.new(start_at, end_at, params) }
+
+  let(:domain) { 'example.com' }
+
+  let(:start_at) { 2.days.ago }
+  let(:end_at)   { Time.now.utc }
+
+  let(:params) { ActionController::Parameters.new(domain: domain) }
+
+  before do
+    local_account = Fabricate(:account)
+
+    Fabricate(:account, domain: domain).follow!(local_account)
+    Fabricate(:account, domain: domain).follow!(local_account)
+    Fabricate(:account, domain: domain)
+
+    Fabricate(:account, domain: "foo.#{domain}").follow!(local_account)
+    Fabricate(:account, domain: "foo.#{domain}").follow!(local_account)
+    Fabricate(:account, domain: "bar.#{domain}")
+  end
+
+  describe 'total' do
+    context 'without include_subdomains' do
+      it 'returns the expected number of accounts' do
+        expect(measure.total).to eq 2
+      end
+    end
+
+    context 'with include_subdomains' do
+      let(:params) { ActionController::Parameters.new(domain: domain, include_subdomains: 'true') }
+
+      it 'returns the expected number of accounts' do
+        expect(measure.total).to eq 4
+      end
+    end
+  end
+end
diff --git a/spec/lib/admin/metrics/measure/instance_follows_measure_spec.rb b/spec/lib/admin/metrics/measure/instance_follows_measure_spec.rb
new file mode 100644
index 0000000000..335e3c7321
--- /dev/null
+++ b/spec/lib/admin/metrics/measure/instance_follows_measure_spec.rb
@@ -0,0 +1,42 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+describe Admin::Metrics::Measure::InstanceFollowsMeasure do
+  subject(:measure) { described_class.new(start_at, end_at, params) }
+
+  let(:domain) { 'example.com' }
+
+  let(:start_at) { 2.days.ago }
+  let(:end_at)   { Time.now.utc }
+
+  let(:params) { ActionController::Parameters.new(domain: domain) }
+
+  before do
+    local_account = Fabricate(:account)
+
+    local_account.follow!(Fabricate(:account, domain: domain))
+    local_account.follow!(Fabricate(:account, domain: domain))
+    Fabricate(:account, domain: domain)
+
+    local_account.follow!(Fabricate(:account, domain: "foo.#{domain}"))
+    local_account.follow!(Fabricate(:account, domain: "foo.#{domain}"))
+    Fabricate(:account, domain: "bar.#{domain}")
+  end
+
+  describe 'total' do
+    context 'without include_subdomains' do
+      it 'returns the expected number of accounts' do
+        expect(measure.total).to eq 2
+      end
+    end
+
+    context 'with include_subdomains' do
+      let(:params) { ActionController::Parameters.new(domain: domain, include_subdomains: 'true') }
+
+      it 'returns the expected number of accounts' do
+        expect(measure.total).to eq 4
+      end
+    end
+  end
+end
diff --git a/spec/lib/admin/metrics/measure/instance_media_attachments_measure_spec.rb b/spec/lib/admin/metrics/measure/instance_media_attachments_measure_spec.rb
new file mode 100644
index 0000000000..711a2aff05
--- /dev/null
+++ b/spec/lib/admin/metrics/measure/instance_media_attachments_measure_spec.rb
@@ -0,0 +1,43 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+describe Admin::Metrics::Measure::InstanceMediaAttachmentsMeasure do
+  subject(:measure) { described_class.new(start_at, end_at, params) }
+
+  let(:domain) { 'example.com' }
+
+  let(:start_at) { 2.days.ago }
+  let(:end_at)   { Time.now.utc }
+
+  let(:params) { ActionController::Parameters.new(domain: domain) }
+
+  let(:remote_account) { Fabricate(:account, domain: domain) }
+  let(:remote_account_on_subdomain) { Fabricate(:account, domain: "foo.#{domain}") }
+
+  before do
+    remote_account.media_attachments.create!(file: attachment_fixture('attachment.jpg'))
+    remote_account_on_subdomain.media_attachments.create!(file: attachment_fixture('attachment.jpg'))
+  end
+
+  describe 'total' do
+    context 'without include_subdomains' do
+      it 'returns the expected number of accounts' do
+        expected_total = remote_account.media_attachments.sum(:file_file_size) + remote_account.media_attachments.sum(:thumbnail_file_size)
+        expect(measure.total).to eq expected_total
+      end
+    end
+
+    context 'with include_subdomains' do
+      let(:params) { ActionController::Parameters.new(domain: domain, include_subdomains: 'true') }
+
+      it 'returns the expected number of accounts' do
+        expected_total = [remote_account, remote_account_on_subdomain].sum do |account|
+          account.media_attachments.sum(:file_file_size) + account.media_attachments.sum(:thumbnail_file_size)
+        end
+
+        expect(measure.total).to eq expected_total
+      end
+    end
+  end
+end
diff --git a/spec/lib/admin/metrics/measure/instance_reports_measure_spec.rb b/spec/lib/admin/metrics/measure/instance_reports_measure_spec.rb
new file mode 100644
index 0000000000..f0ffd39cfb
--- /dev/null
+++ b/spec/lib/admin/metrics/measure/instance_reports_measure_spec.rb
@@ -0,0 +1,39 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+describe Admin::Metrics::Measure::InstanceReportsMeasure do
+  subject(:measure) { described_class.new(start_at, end_at, params) }
+
+  let(:domain) { 'example.com' }
+
+  let(:start_at) { 2.days.ago }
+  let(:end_at)   { Time.now.utc }
+
+  let(:params) { ActionController::Parameters.new(domain: domain) }
+
+  before do
+    Fabricate(:report, target_account: Fabricate(:account, domain: domain))
+    Fabricate(:report, target_account: Fabricate(:account, domain: domain))
+
+    Fabricate(:report, target_account: Fabricate(:account, domain: "foo.#{domain}"))
+    Fabricate(:report, target_account: Fabricate(:account, domain: "foo.#{domain}"))
+    Fabricate(:report, target_account: Fabricate(:account, domain: "bar.#{domain}"))
+  end
+
+  describe 'total' do
+    context 'without include_subdomains' do
+      it 'returns the expected number of accounts' do
+        expect(measure.total).to eq 2
+      end
+    end
+
+    context 'with include_subdomains' do
+      let(:params) { ActionController::Parameters.new(domain: domain, include_subdomains: 'true') }
+
+      it 'returns the expected number of accounts' do
+        expect(measure.total).to eq 5
+      end
+    end
+  end
+end
diff --git a/spec/lib/admin/metrics/measure/instance_statuses_measure_spec.rb b/spec/lib/admin/metrics/measure/instance_statuses_measure_spec.rb
new file mode 100644
index 0000000000..c1425ecdb9
--- /dev/null
+++ b/spec/lib/admin/metrics/measure/instance_statuses_measure_spec.rb
@@ -0,0 +1,39 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+describe Admin::Metrics::Measure::InstanceStatusesMeasure do
+  subject(:measure) { described_class.new(start_at, end_at, params) }
+
+  let(:domain) { 'example.com' }
+
+  let(:start_at) { 2.days.ago }
+  let(:end_at)   { Time.now.utc }
+
+  let(:params) { ActionController::Parameters.new(domain: domain) }
+
+  before do
+    Fabricate(:status, account: Fabricate(:account, domain: domain))
+    Fabricate(:status, account: Fabricate(:account, domain: domain))
+
+    Fabricate(:status, account: Fabricate(:account, domain: "foo.#{domain}"))
+    Fabricate(:status, account: Fabricate(:account, domain: "foo.#{domain}"))
+    Fabricate(:status, account: Fabricate(:account, domain: "bar.#{domain}"))
+  end
+
+  describe 'total' do
+    context 'without include_subdomains' do
+      it 'returns the expected number of accounts' do
+        expect(measure.total).to eq 2
+      end
+    end
+
+    context 'with include_subdomains' do
+      let(:params) { ActionController::Parameters.new(domain: domain, include_subdomains: 'true') }
+
+      it 'returns the expected number of accounts' do
+        expect(measure.total).to eq 5
+      end
+    end
+  end
+end