diff --git a/protocol.go b/protocol.go
index ff3abb7..16e1f3b 100644
--- a/protocol.go
+++ b/protocol.go
@@ -627,12 +627,13 @@ func (session *session) handleXCLIENT(cmd command) {
 }
 
 func (session *session) handlePROXY(cmd command) {
-
+	session.logf("Proxy command: %s", cmd.line)
+	// http://www.haproxy.org/download/1.8/doc/proxy-protocol.txt
+	// Example:  `PROXY TCP4 8.8.8.8 127.0.0.1 443 25`
 	if !session.server.EnableProxyProtocol {
 		session.reply(550, "Proxy Protocol not enabled")
 		return
 	}
-
 	if len(cmd.fields) < 6 {
 		session.reply(502, "Couldn't decode the command.")
 		return
@@ -643,7 +644,6 @@ func (session *session) handlePROXY(cmd command) {
 		newTCPPort uint64 = 0
 		err        error
 	)
-
 	newAddr = net.ParseIP(cmd.fields[2])
 
 	newTCPPort, err = strconv.ParseUint(cmd.fields[4], 10, 16)
@@ -665,6 +665,9 @@ func (session *session) handlePROXY(cmd command) {
 	if newTCPPort != 0 {
 		tcpAddr.Port = int(newTCPPort)
 	}
+	session.logf("Proxy processed: new address - %s:%v",
+		tcpAddr.IP, tcpAddr.Port,
+	)
 
 	session.welcome()
 
diff --git a/smtpd_test.go b/smtpd_test.go
index 09a2121..6b946b0 100644
--- a/smtpd_test.go
+++ b/smtpd_test.go
@@ -1590,6 +1590,35 @@ func TestMailformedMAILFROM(t *testing.T) {
 	}
 }
 
+func TestProxyNotEnabled(t *testing.T) {
+	addr, closer := runserver(t, &smtpd.Server{
+		EnableProxyProtocol: false, // important
+		ProtocolLogger:      log.New(os.Stdout, "log: ", log.Lshortfile),
+	})
+	defer closer()
+
+	c, err := smtp.Dial(addr)
+	if err != nil {
+		t.Fatalf("Dial failed: %v", err)
+	}
+
+	where := strings.Split(addr, ":")
+	err = cmd(c.Text, 550, "PROXY TCP4 8.8.8.8 %s 443 %s", where[0], where[1])
+	if err != nil {
+		t.Fatalf("sending proxy command enabled from the box - %s", err)
+	}
+
+	err = c.Hello("nobody.example.org")
+	if err != nil {
+		t.Fatalf("sending helo command failed with %s", err)
+	}
+
+	err = c.Quit()
+	if err != nil {
+		t.Fatalf("sending quit command failed with %s", err)
+	}
+}
+
 func TestTLSListener(t *testing.T) {
 
 	cert, err := tls.X509KeyPair(localhostCert, localhostKey)