new file mode 100644
--- /dev/null
+++ b/smtp.conf
@@ -0,0 +1,54 @@
+# Config for smtp.t tests.
+
+worker_processes  1;
+
+master_process off;
+daemon         off;
+
+events {
+    worker_connections  1024;
+}
+
+mail {
+    proxy_pass_error_message  on;
+    auth_http  http://localhost:8080/mail/auth;
+    xclient    off;
+
+    server {
+        listen     10025;
+        protocol   smtp;
+        smtp_auth  login plain none;
+    }
+
+    server {
+        listen     10026;
+        protocol   smtp;
+        smtp_greeting_delay  100ms;
+    }
+}
+
+http {
+    access_log    off;
+
+    server {
+        listen       8080;
+        server_name  localhost;
+
+        location = /mail/auth {
+            set $reply ERROR;
+
+            if ($http_auth_smtp_to ~ example.com) {
+                set $reply OK;
+            }
+            if ($http_auth_pass ~ secret) {
+                set $reply OK;
+            }
+
+            add_header Auth-Status $reply;
+            add_header Auth-Server 127.0.0.1;
+            add_header Auth-Port 25;
+            add_header Auth-Wait 1;
+            return 204;
+        }
+    }
+}

--- a/smtp.t
+++ b/smtp.t
@@ -9,8 +9,9 @@
 use warnings;
 use strict;
 
-use Test::More tests => 26;
+use Test::More tests => 28;
 
+use File::Temp qw/ tempdir /;
 use IO::Socket;
 use MIME::Base64;
 
@@ -19,6 +20,35 @@ use constant CRLF => "\x0D\x0A";
 select STDERR; $| = 1;
 select STDOUT; $| = 1;
 
+###############################################################################
+
+# Create temp directory and run nginx instance.
+
+my $tempdir = tempdir('nginx-test-XXXXXXXXXX', TMPDIR => 1, CLEANUP => 1)
+	or die "Can't create temp directory: $!\n";
+
+my $pid = fork();
+die "Unable to fork(): $!\n" unless defined $pid;
+
+if ($pid == 0) {
+	exec('../nginx/objs/nginx', '-c', 'smtp.conf', '-g',
+		"pid $tempdir/nginx.pid; error_log $tempdir/nginx-error.log info;")
+		or die "Unable to exec(): $!\n";
+	print "# child after exec - not reached\n";
+}
+
+END {
+	# terminate nginx by SIGTERM
+	kill 15, $pid;
+	wait;
+}
+
+# Give nginx some time to start.
+
+sleep 1;
+
+###############################################################################
+
 my $s = smtp_connect();
 smtp_check(qr/^220 /, "greeting");