diff --git a/.reek.yml b/.reek.yml
index 26ba7e8..675aa8a 100644
--- a/.reek.yml
+++ b/.reek.yml
@@ -45,7 +45,7 @@ detectors:
       - Truemail::Log::Serializer::Base#errors
       - Truemail::Log::Serializer::ValidatorBase#replace_invalid_chars
       - Truemail::Dns::Worker#nameserver_port
-      - Truemail::Configuration#dns_server_matcher
+      - Truemail::Configuration#check_dns_settings
 
   ControlParameter:
     exclude:
@@ -77,6 +77,7 @@ detectors:
 
   TooManyConstants:
     exclude:
+      - Truemail::Configuration
       - Truemail::RegexConstant
 
 exclude_paths:
diff --git a/lib/truemail/configuration.rb b/lib/truemail/configuration.rb
index ab6b18a..7f25396 100644
--- a/lib/truemail/configuration.rb
+++ b/lib/truemail/configuration.rb
@@ -7,20 +7,23 @@ class Configuration
     DEFAULT_CONNECTION_ATTEMPTS = 2
     DEFAULT_VALIDATION_TYPE = :smtp
     DEFAULT_LOGGER_OPTIONS = { tracking_event: :error, stdout: false, log_absolute_path: nil }.freeze
-
-    attr_reader :email_pattern,
-                :smtp_error_body_pattern,
-                :verifier_email,
+    SETTERS = %i[
+      email_pattern
+      smtp_error_body_pattern
+      connection_timeout
+      response_timeout
+      connection_attempts
+      whitelisted_domains
+      blacklisted_domains
+    ].freeze
+
+    attr_reader :verifier_email,
                 :verifier_domain,
-                :connection_timeout,
-                :response_timeout,
-                :connection_attempts,
                 :default_validation_type,
                 :validation_type_by_domain,
-                :whitelisted_domains,
-                :blacklisted_domains,
                 :dns,
-                :logger
+                :logger,
+                *Truemail::Configuration::SETTERS
 
     attr_accessor :whitelist_validation, :not_rfc_mx_lookup_flow, :smtp_fail_fast, :smtp_safe_check
 
@@ -31,13 +34,6 @@ def initialize(&block)
       tap(&block) if block
     end
 
-    %i[email_pattern smtp_error_body_pattern].each do |method|
-      define_method("#{method}=") do |argument|
-        raise_unless(argument, __method__, argument.is_a?(::Regexp))
-        instance_variable_set(:"@#{method}", argument)
-      end
-    end
-
     def verifier_email=(email)
       validate_arguments(email, __method__)
       @verifier_email = email.downcase
@@ -49,13 +45,6 @@ def verifier_domain=(domain)
       @verifier_domain = domain.downcase
     end
 
-    %i[connection_timeout response_timeout connection_attempts].each do |method|
-      define_method("#{method}=") do |argument|
-        raise_unless(argument, __method__, argument.is_a?(::Integer) && argument.positive?)
-        instance_variable_set(:"@#{method}", argument)
-      end
-    end
-
     def default_validation_type=(argument)
       raise_unless(argument, __method__, argument.is_a?(::Symbol) && Truemail::Validator::VALIDATION_TYPES.include?(argument))
       @default_validation_type = argument
@@ -66,9 +55,17 @@ def validation_type_for=(settings)
       validation_type_by_domain.merge!(settings)
     end
 
-    %i[whitelisted_domains blacklisted_domains dns].each do |method|
+    def argument_consistent?(argument)
+      case argument
+      when ::Array then check_domain_list(argument)
+      when ::Integer then argument.positive?
+      when ::Regexp then true
+      end
+    end
+
+    Truemail::Configuration::SETTERS.each do |method|
       define_method("#{method}=") do |argument|
-        raise_unless(argument, __method__, argument.is_a?(::Array) && check_domain_list(argument))
+        raise_unless(argument, __method__, argument_consistent?(argument))
         instance_variable_set(:"@#{method}", argument)
       end
     end
@@ -151,12 +148,8 @@ def validate_validation_type(settings)
       end
     end
 
-    def dns_server_matcher
-      ->(dns_server) { Truemail::RegexConstant::REGEX_DNS_SERVER_ADDRESS_PATTERN.match?(dns_server.to_s) }
-    end
-
     def check_dns_settings(dns_servers)
-      dns_servers.all?(&dns_server_matcher)
+      dns_servers.all? { |dns_server| Truemail::RegexConstant::REGEX_DNS_SERVER_ADDRESS_PATTERN.match?(dns_server.to_s) }
     end
 
     def logger_options(current_options)
diff --git a/spec/truemail/audit/dns_spec.rb b/spec/truemail/audit/dns_spec.rb
index f55c1af..53a842e 100644
--- a/spec/truemail/audit/dns_spec.rb
+++ b/spec/truemail/audit/dns_spec.rb
@@ -62,7 +62,7 @@
       end
 
       context 'when a record of verifier domain not refers to currernt host ip address' do
-        before { dns_mock_server.assign_mocks(verifier_domain => { a: [current_host_ip.next] }) }
+        before { dns_mock_server.assign_mocks(verifier_domain => { a: [Faker::Internet.ip_v4_address] }) }
 
         include_examples 'addes verifier domain not refer warning to result instance'
       end
diff --git a/spec/truemail/configuration_spec.rb b/spec/truemail/configuration_spec.rb
index 0e6c2e1..c55ee79 100644
--- a/spec/truemail/configuration_spec.rb
+++ b/spec/truemail/configuration_spec.rb
@@ -30,6 +30,22 @@
       specify { expect(described_class).to be_const_defined(:DEFAULT_LOGGER_OPTIONS) }
       specify { expect(described_class::DEFAULT_LOGGER_OPTIONS).to eq(tracking_event: :error, stdout: false, log_absolute_path: nil) }
     end
+
+    context 'SETTERS' do
+      specify { expect(described_class).to be_const_defined(:SETTERS) }
+
+      specify do
+        expect(described_class::SETTERS).to include(
+          :email_pattern,
+          :smtp_error_body_pattern,
+          :connection_timeout,
+          :response_timeout,
+          :connection_attempts,
+          :whitelisted_domains,
+          :blacklisted_domains
+        )
+      end
+    end
   end
 
   describe '.new' do