+mail from:<c@example.com>
+??? 250
+rcpt to:<fred@test.ex>
+??? 250
+quit
+****
+client HOSTIPV4 PORT_D
+??? 220
+helo testclient
+??? 250
+mail from:<b@test.example.com>
+??? 250
+rcpt to:<fred@test.ex>
+??? 550
+quit
+****
+client 127.0.0.1 PORT_D2
+??? 220
+helo testclient
+??? 250
+mail from:<c@example.com>
+??? 250
+rcpt to:<fred@test.ex>
+??? 550
+quit
+****
+#
+#
+#
+#
+#
+# helo name gets used when mailfrom is null
+client HOSTIPV4 PORT_S
+??? 220
+helo passme.helo.example.com
+??? 250
+mail from:<>