diff --git a/app/controllers/admin/email_domain_blocks_controller.rb b/app/controllers/admin/email_domain_blocks_controller.rb
index 9fe85064e..c25919726 100644
--- a/app/controllers/admin/email_domain_blocks_controller.rb
+++ b/app/controllers/admin/email_domain_blocks_controller.rb
@@ -6,12 +6,12 @@ module Admin
 
     def index
       authorize :email_domain_block, :index?
-      @email_domain_blocks = EmailDomainBlock.page(params[:page])
+      @email_domain_blocks = EmailDomainBlock.where(parent_id: nil).includes(:children).order(id: :desc).page(params[:page])
     end
 
     def new
       authorize :email_domain_block, :create?
-      @email_domain_block = EmailDomainBlock.new
+      @email_domain_block = EmailDomainBlock.new(domain: params[:_domain])
     end
 
     def create
@@ -21,6 +21,28 @@ module Admin
 
       if @email_domain_block.save
         log_action :create, @email_domain_block
+
+        if @email_domain_block.with_dns_records?
+          hostnames = []
+          ips       = []
+
+          Resolv::DNS.open do |dns|
+            dns.timeouts = 1
+
+            hostnames = dns.getresources(@email_domain_block.domain, Resolv::DNS::Resource::IN::MX).to_a.map { |e| e.exchange.to_s }
+
+            ([@email_domain_block.domain] + hostnames).uniq.each do |hostname|
+              ips.concat(dns.getresources(hostname, Resolv::DNS::Resource::IN::A).to_a.map { |e| e.address.to_s })
+              ips.concat(dns.getresources(hostname, Resolv::DNS::Resource::IN::AAAA).to_a.map { |e| e.address.to_s })
+            end
+          end
+
+          (hostnames + ips).each do |hostname|
+            another_email_domain_block = EmailDomainBlock.new(domain: hostname, parent: @email_domain_block)
+            log_action :create, another_email_domain_block if another_email_domain_block.save
+          end
+        end
+
         redirect_to admin_email_domain_blocks_path, notice: I18n.t('admin.email_domain_blocks.created_msg')
       else
         render :new
@@ -41,7 +63,7 @@ module Admin
     end
 
     def resource_params
-      params.require(:email_domain_block).permit(:domain)
+      params.require(:email_domain_block).permit(:domain, :with_dns_records)
     end
   end
 end
diff --git a/app/models/email_domain_block.rb b/app/models/email_domain_block.rb
index bc70dea25..f50fa46ba 100644
--- a/app/models/email_domain_block.rb
+++ b/app/models/email_domain_block.rb
@@ -7,13 +7,27 @@
 #  domain     :string           default(""), not null
 #  created_at :datetime         not null
 #  updated_at :datetime         not null
+#  parent_id  :bigint(8)
 #
 
 class EmailDomainBlock < ApplicationRecord
   include DomainNormalizable
 
+  belongs_to :parent, class_name: 'EmailDomainBlock', optional: true
+  has_many :children, class_name: 'EmailDomainBlock', foreign_key: :parent_id, inverse_of: :parent, dependent: :destroy
+
   validates :domain, presence: true, uniqueness: true, domain: true
 
+  def with_dns_records=(val)
+    @with_dns_records = ActiveModel::Type::Boolean.new.cast(val)
+  end
+
+  def with_dns_records?
+    @with_dns_records
+  end
+
+  alias with_dns_records with_dns_records?
+
   def self.block?(email)
     _, domain = email.split('@', 2)
 
diff --git a/app/views/admin/accounts/show.html.haml b/app/views/admin/accounts/show.html.haml
index a30b78db2..744d17d1f 100644
--- a/app/views/admin/accounts/show.html.haml
+++ b/app/views/admin/accounts/show.html.haml
@@ -96,10 +96,17 @@
               = table_link_to 'angle-double-down', t('admin.accounts.demote'), demote_admin_account_role_path(@account.id), method: :post, data: { confirm: t('admin.accounts.are_you_sure') } if can?(:demote, @account.user)
 
           %tr
-            %th= t('admin.accounts.email')
-            %td= @account.user_email
+            %th{ rowspan: can?(:create, :email_domain_block) ? 3 : 2 }= t('admin.accounts.email')
+            %td{ rowspan: can?(:create, :email_domain_block) ? 3 : 2 }= @account.user_email
             %td= table_link_to 'edit', t('admin.accounts.change_email.label'), admin_account_change_email_path(@account.id) if can?(:change_email, @account.user)
 
+          %tr
+            %td= table_link_to 'search', t('admin.accounts.search_same_email_domain'), admin_accounts_path(email: "%@#{@account.user_email.split('@').last}")
+
+          - if can?(:create, :email_domain_block)
+            %tr
+              %td= table_link_to 'ban', t('admin.accounts.add_email_domain_block'), new_admin_email_domain_block_path(_domain: @account.user_email.split('@').last)
+
           - if @account.user_unconfirmed_email.present?
             %tr
               %th= t('admin.accounts.unconfirmed_email')
@@ -204,7 +211,7 @@
         = link_to t('admin.accounts.perform_full_suspension'), new_admin_account_action_path(@account.id, type: 'suspend'), class: 'button button--destructive' if can?(:suspend, @account)
 
       - unless @account.local?
-        - if DomainBlock.where(domain: @account.domain).exists?
+        - if DomainBlock.rule_for(@account.domain)
           = link_to t('admin.domain_blocks.view'), admin_instance_path(@account.domain), class: 'button'
         - else
           = link_to t('admin.domain_blocks.add_new'), new_admin_domain_block_path(_domain: @account.domain), class: 'button button--destructive'
diff --git a/app/views/admin/email_domain_blocks/_email_domain_block.html.haml b/app/views/admin/email_domain_blocks/_email_domain_block.html.haml
index bf66c9001..41ab8c171 100644
--- a/app/views/admin/email_domain_blocks/_email_domain_block.html.haml
+++ b/app/views/admin/email_domain_blocks/_email_domain_block.html.haml
@@ -3,3 +3,13 @@
     %samp= email_domain_block.domain
   %td
     = table_link_to 'trash', t('admin.email_domain_blocks.delete'), admin_email_domain_block_path(email_domain_block), method: :delete
+
+- email_domain_block.children.each do |child_email_domain_block|
+  %tr
+    %td
+      %samp= child_email_domain_block.domain
+      %span.muted-hint
+        = surround '(', ')' do
+          = t('admin.email_domain_blocks.from_html', domain: content_tag(:samp, email_domain_block.domain))
+    %td
+      = table_link_to 'trash', t('admin.email_domain_blocks.delete'), admin_email_domain_block_path(child_email_domain_block), method: :delete
diff --git a/app/views/admin/email_domain_blocks/new.html.haml b/app/views/admin/email_domain_blocks/new.html.haml
index f372fa512..4a346f240 100644
--- a/app/views/admin/email_domain_blocks/new.html.haml
+++ b/app/views/admin/email_domain_blocks/new.html.haml
@@ -5,7 +5,10 @@
   = render 'shared/error_messages', object: @email_domain_block
 
   .fields-group
-    = f.input :domain, wrapper: :with_label, label: t('admin.email_domain_blocks.domain')
+    = f.input :domain, wrapper: :with_block_label, label: t('admin.email_domain_blocks.domain')
+
+  .fields-group
+    = f.input :with_dns_records, as: :boolean, wrapper: :with_label
 
   .actions
     = f.button :button, t('.create'), type: :submit
diff --git a/config/locales/en.yml b/config/locales/en.yml
index 05d92b121..13f22d922 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -92,6 +92,7 @@ en:
       delete: Delete
       destroyed_msg: Moderation note successfully destroyed!
     accounts:
+      add_email_domain_block: Blacklist e-mail domain
       approve: Approve
       approve_all: Approve all
       are_you_sure: Are you sure?
@@ -172,6 +173,7 @@ en:
         staff: Staff
         user: User
       search: Search
+      search_same_email_domain: Other users with the same e-mail domain
       search_same_ip: Other users with the same IP
       shared_inbox_url: Shared inbox URL
       show:
@@ -358,6 +360,7 @@ en:
       destroyed_msg: Successfully deleted e-mail domain from blacklist
       domain: Domain
       empty: No e-mail domains currently blacklisted.
+      from_html: from %{domain}
       new:
         create: Add domain
         title: New e-mail blacklist entry
diff --git a/config/locales/simple_form.en.yml b/config/locales/simple_form.en.yml
index f279a8e4f..fd56a35bf 100644
--- a/config/locales/simple_form.en.yml
+++ b/config/locales/simple_form.en.yml
@@ -54,6 +54,9 @@ en:
         whole_word: When the keyword or phrase is alphanumeric only, it will only be applied if it matches the whole word
       domain_allow:
         domain: This domain will be able to fetch data from this server and incoming data from it will be processed and stored
+      email_domain_block:
+        domain: This can be the domain name that shows up in the e-mail address, the MX record that domain resolves to, or IP of the server that MX record resolves to. Those will be checked upon user sign-up and the sign-up will be rejected.
+        with_dns_records: An attempt to resolve the given domain's DNS records will be made and the results will also be blacklisted
       featured_tag:
         name: 'You might want to use one of these:'
       form_challenge:
@@ -152,6 +155,8 @@ en:
         username: Username
         username_or_email: Username or Email
         whole_word: Whole word
+      email_domain_block:
+        with_dns_records: Include MX records and IPs of the domain
       featured_tag:
         name: Hashtag
       interactions:
diff --git a/db/migrate/20200312185443_add_parent_id_to_email_domain_blocks.rb b/db/migrate/20200312185443_add_parent_id_to_email_domain_blocks.rb
new file mode 100644
index 000000000..03915040c
--- /dev/null
+++ b/db/migrate/20200312185443_add_parent_id_to_email_domain_blocks.rb
@@ -0,0 +1,5 @@
+class AddParentIdToEmailDomainBlocks < ActiveRecord::Migration[5.2]
+  def change
+    add_reference :email_domain_blocks, :parent, null: true, default: nil, foreign_key: { on_delete: :cascade, to_table: :email_domain_blocks }, index: false
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index 5d3651e52..7f28f2ec4 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 2020_03_12_144258) do
+ActiveRecord::Schema.define(version: 2020_03_12_185443) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -336,6 +336,7 @@ ActiveRecord::Schema.define(version: 2020_03_12_144258) do
     t.string "domain", default: "", null: false
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
+    t.bigint "parent_id"
     t.index ["domain"], name: "index_email_domain_blocks_on_domain", unique: true
   end
 
@@ -869,6 +870,7 @@ ActiveRecord::Schema.define(version: 2020_03_12_144258) do
   add_foreign_key "conversation_mutes", "accounts", name: "fk_225b4212bb", on_delete: :cascade
   add_foreign_key "conversation_mutes", "conversations", on_delete: :cascade
   add_foreign_key "custom_filters", "accounts", on_delete: :cascade
+  add_foreign_key "email_domain_blocks", "email_domain_blocks", column: "parent_id", on_delete: :cascade
   add_foreign_key "favourites", "accounts", name: "fk_5eb6c2b873", on_delete: :cascade
   add_foreign_key "favourites", "statuses", name: "fk_b0e856845e", on_delete: :cascade
   add_foreign_key "featured_tags", "accounts", on_delete: :cascade