diff --git a/t/stream_proxy_protocol_v2_ipv6.t b/t/stream_proxy_protocol_v2_ipv6.t
new file mode 100644
index 000000000..679c31899
--- /dev/null
+++ b/t/stream_proxy_protocol_v2_ipv6.t
@@ -0,0 +1,166 @@
+#!/usr/bin/perl
+
+# (C) Nginx, Inc.
+
+# Tests for PROXY protocol v2 IPv6 upstream write in stream proxy.
+
+###############################################################################
+
+use warnings;
+use strict;
+
+use Test::More;
+
+use IO::Select;
+use Socket qw/ inet_pton AF_INET6 /;
+
+BEGIN { use FindBin; chdir($FindBin::Bin); }
+
+use lib 'lib';
+use Test::Nginx;
+
+###############################################################################
+
+select STDERR; $| = 1;
+select STDOUT; $| = 1;
+
+eval { require IO::Socket::IP; };
+plan(skip_all => 'IO::Socket::IP not installed') if $@;
+
+# Verify IPv6 loopback is available on this system.
+eval {
+	IO::Socket::IP->new(
+		LocalHost => '::1',
+		LocalPort => 0,
+		Proto     => 'tcp',
+		Listen    => 1,
+	) or die "$!";
+};
+plan(skip_all => 'no IPv6 loopback') if $@;
+
+# PPv2 magic signature (12 bytes)
+my $SIG = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
+
+# Fixed header: 16 bytes.  IPv6 address block: 36 bytes.  Total: 52 bytes.
+my $PPV2_HDR = 52;
+
+my $t = Test::Nginx->new()->has(qw/stream/)->plan(9)
+	->write_file_expand('nginx.conf', <<'EOF');
+
+%%TEST_GLOBALS%%
+
+daemon off;
+
+events {
+}
+
+stream {
+    %%TEST_GLOBALS_STREAM%%
+
+    server {
+        listen          [::1]:%%PORT_8083%%;
+        proxy_pass      127.0.0.1:8081;
+        proxy_protocol  on;
+        proxy_protocol_version 2;
+    }
+}
+
+EOF
+
+$t->run_daemon(\&stream_daemon, port(8081));
+$t->run();
+$t->waitforsocket('127.0.0.1:' . port(8081));
+
+###############################################################################
+
+my $dp = port(8083);
+
+my $s = IO::Socket::IP->new(
+	Proto    => 'tcp',
+	PeerHost => '::1',
+	PeerPort => $dp,
+) or die "Can't connect to nginx: $!\n";
+$s->autoflush(1);
+
+my $sp = $s->sockport();
+
+$s->syswrite('hello');
+
+my $data = '';
+my $sel  = IO::Select->new($s);
+while ($sel->can_read(5)) {
+	my $n = $s->sysread(my $buf, 65536);
+	last unless $n;
+	$data .= $buf;
+	last if length($data) >= $PPV2_HDR + 5;
+}
+
+is(substr($data, 0, 12), $SIG,                              'ipv6 v2 signature');
+is(unpack('C', substr($data, 12, 1)), 0x21,                  'ipv6 v2 version and command');
+is(unpack('C', substr($data, 13, 1)), 0x21,                  'ipv6 v2 AF_INET6 STREAM');
+is(unpack('n', substr($data, 14, 2)), 36,                    'ipv6 v2 addr block length');
+is(substr($data, 16, 16), inet_pton(AF_INET6, '::1'),        'ipv6 v2 src addr');
+is(substr($data, 32, 16), inet_pton(AF_INET6, '::1'),        'ipv6 v2 dst addr');
+is(unpack('n', substr($data, 48, 2)), $sp,                   'ipv6 v2 src port');
+is(unpack('n', substr($data, 50, 2)), $dp,                   'ipv6 v2 dst port');
+is(substr($data, $PPV2_HDR), 'hello',                        'ipv6 v2 payload after header');
+
+###############################################################################
+
+sub stream_daemon {
+	my ($port_num) = @_;
+
+	my $server = IO::Socket::INET->new(
+		Proto     => 'tcp',
+		LocalAddr => '127.0.0.1:' . $port_num,
+		Listen    => 5,
+		Reuse     => 1
+	)
+		or die "Can't create listening socket: $!\n";
+
+	my $sel = IO::Select->new($server);
+
+	local $SIG{PIPE} = 'IGNORE';
+
+	while (my @ready = $sel->can_read) {
+		foreach my $fh (@ready) {
+			if ($server == $fh) {
+				my $new = $fh->accept;
+				$new->autoflush(1);
+				$sel->add($new);
+
+			} elsif (stream_handle_client($fh)) {
+				$sel->remove($fh);
+				$fh->close;
+			}
+		}
+	}
+}
+
+sub stream_handle_client {
+	my ($client) = @_;
+
+	log2c("(new connection $client)");
+
+	my $buffer = '';
+	my $csel = IO::Select->new($client);
+	while ($csel->can_read(0.5)) {
+		my $n = $client->sysread(my $chunk, 65536);
+		last unless $n;
+		$buffer .= $chunk;
+	}
+
+	log2i("$client recv " . length($buffer) . " bytes");
+
+	$client->syswrite($buffer);
+
+	log2o("$client sent " . length($buffer) . " bytes");
+
+	return 1;
+}
+
+sub log2i { Test::Nginx::log_core('|| <<', @_); }
+sub log2o { Test::Nginx::log_core('|| >>', @_); }
+sub log2c { Test::Nginx::log_core('||',    @_); }
+
+###############################################################################