Fixed issue#240 - TLS/SSL for SMTP with exchange. Improved Net::SMTP.do_start to auto detect available auth types based on SMTP server capabilities.

app/models/channel/driver/smtp.rb

@@ -10,8 +10,10 @@ class Channel::Driver::Smtp
       host:                 'some.host',
       port:                 25,
       enable_starttls_auto: true, # optional
+      openssl_verify_mode:  'none', # optional
       user:                 'someuser',
       password:             'somepass'
+      authentication:       nil, # nil, autodetection - to use certain schema use 'plain', 'login' or 'cram_md5'
     },
     mail_attributes,
     notification
@@ -28,6 +30,9 @@ class Channel::Driver::Smtp
     if !options.key?(:port)
       options[:port] = 25
     end
+    if !options.key?(:domain)
+      options[:domain] = Setting.get('fqdn')
+    end
     if !options.key?(:enable_starttls_auto)
       options[:enable_starttls_auto] = true
     end
@@ -39,10 +44,11 @@ class Channel::Driver::Smtp
       openssl_verify_mode: options[:openssl_verify_mode],
       address: options[:host],
       port: options[:port],
-      domain: options[:host],
+      domain: options[:domain],
       user_name: options[:user],
       password: options[:password],
       enable_starttls_auto: options[:enable_starttls_auto],
+      authentication: options[:authentication],
     }
     mail.deliver
   end

lib/core_ext/net/smtp.rb

@@ -0,0 +1,52 @@
+# rubocop:disable all
+module Net
+  class SMTP
+    def do_start(helo_domain, user, secret, authtype)
+      raise IOError, 'SMTP session already started' if @started
+      if user or secret
+        check_auth_method(authtype || DEFAULT_AUTH_TYPE)
+        check_auth_args user, secret
+      end
+      s = Timeout.timeout(@open_timeout, Net::OpenTimeout) do
+        tcp_socket(@address, @port)
+      end
+      logging "Connection opened: #{@address}:#{@port}"
+      @socket = new_internet_message_io(tls? ? tlsconnect(s) : s)
+      check_response critical { recv_response() }
+      do_helo helo_domain
+      if starttls_always? or (capable_starttls? and starttls_auto?)
+        unless capable_starttls?
+          raise SMTPUnsupportedCommand,
+              "STARTTLS is not supported on this server"
+        end
+        starttls
+        @socket = new_internet_message_io(tlsconnect(s))
+        # helo response may be different after STARTTLS
+        do_helo helo_domain
+        # ADD auto detection of authtype - https://github.com/zammad/zammad/issues/240
+        # set detected authtype based on smtp server capabilities
+        if !authtype
+          if auth_capable?(DEFAULT_AUTH_TYPE)
+            authtype = DEFAULT_AUTH_TYPE
+          elsif capable_plain_auth?
+            authtype = 'PLAIN'
+          elsif capable_login_auth?
+            authtype = 'LOGIN'
+          elsif capable_cram_md5_auth?
+            authtype = 'CRAM-MD5'
+          end
+        end
+        # /ADD auto detection of authtype - https://github.com/zammad/zammad/issues/240
+      end
+      authenticate user, secret, (authtype || DEFAULT_AUTH_TYPE) if user
+      @started = true
+    ensure
+      unless @started
+        # authentication failed, cancel connection.
+        s.close if s and not s.closed?
+        @socket = nil
+      end
+    end
+  end
+end
+# rubocop:enable all