diff --git a/app/models/registrar.rb b/app/models/registrar.rb
index 040c7886b..149bb7541 100644
--- a/app/models/registrar.rb
+++ b/app/models/registrar.rb
@@ -137,7 +137,8 @@ class Registrar < ApplicationRecord
 
   def api_ip_white?(ip)
     return true unless Setting.api_ip_whitelist_enabled
-    white_ips.api.pluck(:ipv4, :ipv6).flatten.include?(ip)
+
+    white_ips.api.include_ip?(ip)
   end
 
   # Audit log is needed, therefore no raw SQL
diff --git a/app/models/white_ip.rb b/app/models/white_ip.rb
index 303ff5886..417633b12 100644
--- a/app/models/white_ip.rb
+++ b/app/models/white_ip.rb
@@ -2,8 +2,8 @@ class WhiteIp < ApplicationRecord
   include Versions
   belongs_to :registrar
 
-  validates :ipv4, format: { with: /\A(([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.){3}([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\z/, allow_blank: true }
-  validates :ipv6, format: { with: /(([0-9a-fA-F]{1,4}:){7,7}[0-9a-fA-F]{1,4}|([0-9a-fA-F]{1,4}:){1,7}:|([0-9a-fA-F]{1,4}:){1,6}:[0-9a-fA-F]{1,4}|([0-9a-fA-F]{1,4}:){1,5}(:[0-9a-fA-F]{1,4}){1,2}|([0-9a-fA-F]{1,4}:){1,4}(:[0-9a-fA-F]{1,4}){1,3}|([0-9a-fA-F]{1,4}:){1,3}(:[0-9a-fA-F]{1,4}){1,4}|([0-9a-fA-F]{1,4}:){1,2}(:[0-9a-fA-F]{1,4}){1,5}|[0-9a-fA-F]{1,4}:((:[0-9a-fA-F]{1,4}){1,6})|:((:[0-9a-fA-F]{1,4}){1,7}|:)|fe80:(:[0-9a-fA-F]{0,4}){0,4}%[0-9a-zA-Z]{1,}|::(ffff(:0{1,4}){0,1}:){0,1}((25[0-5]|(2[0-4]|1{0,1}[0-9]){0,1}[0-9]).){3,3}(25[0-5]|(2[0-4]|1{0,1}[0-9]){0,1}[0-9])|([0-9a-fA-F]{1,4}:){1,4}:((25[0-5]|(2[0-4]|1{0,1}[0-9]){0,1}[0-9]).){3,3}(25[0-5]|(2[0-4]|1{0,1}[0-9]){0,1}[0-9]))/, allow_blank: true }
+  validate :valid_ipv4?
+  validate :valid_ipv6?
 
   validate :validate_ipv4_and_ipv6
   def validate_ipv4_and_ipv6
@@ -11,6 +11,22 @@ class WhiteIp < ApplicationRecord
     errors.add(:base, I18n.t(:ipv4_or_ipv6_must_be_present))
   end
 
+  def valid_ipv4?
+    return if ipv4.blank?
+
+    IPAddr.new(ipv4, Socket::AF_INET)
+  rescue StandardError => _e
+    errors.add(:ipv4, :invalid)
+  end
+
+  def valid_ipv6?
+    return if ipv6.blank?
+
+    IPAddr.new(ipv6, Socket::AF_INET6)
+  rescue StandardError => _e
+    errors.add(:ipv6, :invalid)
+  end
+
   API = 'api'
   REGISTRAR = 'registrar'
   INTERFACES = [API, REGISTRAR]
@@ -23,8 +39,37 @@ class WhiteIp < ApplicationRecord
   end
 
   class << self
+    # rubocop:disable Style/CaseEquality
+    # rubocop:disable Metrics/AbcSize
     def include_ip?(ip)
-      where('ipv4 = :ip OR ipv6 = :ip', ip: ip).any?
+      return false if ip.blank?
+
+      where(id: ids_including(ip)).any?
+    end
+
+    def ids_including(ip)
+      ipv4 = ipv6 = []
+      if check_ip4(ip).present?
+        ipv4 = select { |white_ip| IPAddr.new(white_ip.ipv4, Socket::AF_INET) === check_ip4(ip) }
+      end
+      if check_ip6(ip).present?
+        ipv6 = select { |white_ip| IPAddr.new(white_ip.ipv6, Socket::AF_INET6) === check_ip6(ip) }
+      end
+      (ipv4 + ipv6).pluck(:id).flatten.uniq
+    end
+    # rubocop:enable Style/CaseEquality
+    # rubocop:enable Metrics/AbcSize
+
+    def check_ip4(ip)
+      IPAddr.new(ip, Socket::AF_INET)
+    rescue StandardError => _e
+      nil
+    end
+
+    def check_ip6(ip)
+      IPAddr.new(ip, Socket::AF_INET6)
+    rescue StandardError => _e
+      nil
     end
   end
 end
diff --git a/test/system/registrar_area/base_test.rb b/test/system/registrar_area/base_test.rb
index 67b19a044..2529b009a 100644
--- a/test/system/registrar_area/base_test.rb
+++ b/test/system/registrar_area/base_test.rb
@@ -29,6 +29,16 @@ class RegistrarAreaBaseTestTest < ApplicationSystemTestCase
     assert_button 'Login'
   end
 
+  def test_user_can_access_when_ip_is_whitelisted_with_subnet
+    white_ips(:one).update!(ipv4: '127.0.0.1/32', interfaces: [WhiteIp::REGISTRAR])
+    Setting.registrar_ip_whitelist_enabled = true
+
+    visit new_registrar_user_session_url
+
+    assert_no_text 'Access denied from IP 127.0.0.1'
+    assert_button 'Login'
+  end
+
   def test_user_can_access_when_ip_is_not_whitelisted_and_whitelist_is_disabled
     Setting.registrar_ip_whitelist_enabled = false
     WhiteIp.delete_all