diff --git a/lib/Test/Nginx/SMTP.pm b/lib/Test/Nginx/SMTP.pm
index 8df56b5..f1098c4 100644
--- a/lib/Test/Nginx/SMTP.pm
+++ b/lib/Test/Nginx/SMTP.pm
@@ -100,6 +100,7 @@
 
 sub smtp_test_daemon {
 	my ($port) = @_;
+	my $proxy_protocol;
 
 	my $server = IO::Socket::INET->new(
 		Proto => 'tcp',
@@ -113,6 +114,8 @@
 		$client->autoflush(1);
 		print $client "220 fake esmtp server ready" . CRLF;
 
+		$proxy_protocol = '';
+
 		while (<$client>) {
 			Test::Nginx::log_core('||', $_);
 
@@ -134,6 +137,10 @@
 				print $client '250 rcpt to ok' . CRLF;
 			} elsif (/^xclient/i) {
 				print $client '220 xclient ok' . CRLF;
+			} elsif (/^proxy/i) {
+				$proxy_protocol = $_;
+			} elsif (/^xproxy/i) {
+				print $client '211 ' . $proxy_protocol . CRLF;
 			} else {
 				print $client "500 unknown command" . CRLF;
 			}
diff --git a/mail_proxy_protocol.t b/mail_proxy_protocol.t
index 721fc29..73cd720 100644
--- a/mail_proxy_protocol.t
+++ b/mail_proxy_protocol.t
@@ -40,6 +40,7 @@
 mail {
     proxy_pass_error_message  on;
     proxy_smtp_auth           on;
+    proxy_protocol            on;
     auth_http  http://127.0.0.1:8080/mail/auth;
     smtp_auth  login plain;
 
@@ -90,7 +91,7 @@
 EOF
 
 $t->run_daemon(\&Test::Nginx::SMTP::smtp_test_daemon);
-$t->try_run('no proxy_protocol')->plan(6);
+$t->try_run('no proxy_protocol')->plan(8);
 
 $t->waitforsocket('127.0.0.1:' . port(8026));
 
@@ -108,6 +109,10 @@
 $s->send('AUTH PLAIN ' . encode_base64("\0test\@example.com\0secret", ''));
 $s->authok('auth with proxy_protocol');
 
+$s->send('XPROXY');
+$s->check(qr/^211 PROXY TCP4 127.0.0.1 127.0.0.1 \d+ \d+/,
+	'proxy protocol to backend');
+
 # connection with PROXY protocol and set_realip_from
 
 $s = Test::Nginx::SMTP->new(PeerAddr => '127.0.0.1:' . port(8027));
@@ -121,4 +126,8 @@
 $s->send('AUTH PLAIN ' . encode_base64("\0test\@example.com\0secret", ''));
 $s->authok('auth with proxy_protocol and realip');
 
+$s->send('XPROXY');
+$s->check(qr/^211 PROXY TCP4 192.0.2.1 127.0.0.1 \d+ \d+/,
+	'proxy_protocol to backend and realip');
+
 ###############################################################################