diff --git a/gennghttpxfun.py b/gennghttpxfun.py
index 3114137d..eb95026d 100755
--- a/gennghttpxfun.py
+++ b/gennghttpxfun.py
@@ -100,6 +100,7 @@ OPTIONS = [
     "tls-ticket-key-memcached-max-fail",
     "request-phase-file",
     "response-phase-file",
+    "accept-proxy-protocol",
     "conf",
 ]
 
diff --git a/integration-tests/nghttpx_http2_test.go b/integration-tests/nghttpx_http2_test.go
index 41c527f7..527cf4c8 100644
--- a/integration-tests/nghttpx_http2_test.go
+++ b/integration-tests/nghttpx_http2_test.go
@@ -787,6 +787,362 @@ func TestH2H1Upgrade(t *testing.T) {
 	}
 }
 
+// TestH2H1ProxyProtocolV1TCP4 tests PROXY protocol version 1
+// containing TCP4 entry is accepted and X-Forwarded-For contains
+// advertised src address.
+func TestH2H1ProxyProtocolV1TCP4(t *testing.T) {
+	st := newServerTester([]string{"--accept-proxy-protocol", "--add-x-forwarded-for"}, t, func(w http.ResponseWriter, r *http.Request) {
+		if got, want := r.Header.Get("X-Forwarded-For"), "192.168.0.2"; got != want {
+			t.Errorf("X-Forwarded-For: %v; want %v", got, want)
+		}
+	})
+	defer st.Close()
+
+	st.conn.Write([]byte("PROXY TCP4 192.168.0.2 192.168.0.100 12345 8080\r\n"))
+
+	res, err := st.http2(requestParam{
+		name: "TestH2H1ProxyProtocolV1TCP4",
+	})
+
+	if err != nil {
+		t.Fatalf("Error st.http2() = %v", err)
+	}
+
+	if got, want := res.status, 200; got != want {
+		t.Errorf("res.status: %v; want %v", got, want)
+	}
+}
+
+// TestH2H1ProxyProtocolV1TCP6 tests PROXY protocol version 1
+// containing TCP6 entry is accepted and X-Forwarded-For contains
+// advertised src address.
+func TestH2H1ProxyProtocolV1TCP6(t *testing.T) {
+	st := newServerTester([]string{"--accept-proxy-protocol", "--add-x-forwarded-for"}, t, func(w http.ResponseWriter, r *http.Request) {
+		if got, want := r.Header.Get("X-Forwarded-For"), "2001:0db8:85a3:0000:0000:8a2e:0370:7334"; got != want {
+			t.Errorf("X-Forwarded-For: %v; want %v", got, want)
+		}
+	})
+	defer st.Close()
+
+	st.conn.Write([]byte("PROXY TCP6 2001:0db8:85a3:0000:0000:8a2e:0370:7334 ::1 12345 8080\r\n"))
+
+	res, err := st.http2(requestParam{
+		name: "TestH2H1ProxyProtocolV1TCP6",
+	})
+
+	if err != nil {
+		t.Fatalf("Error st.http2() = %v", err)
+	}
+
+	if got, want := res.status, 200; got != want {
+		t.Errorf("res.status: %v; want %v", got, want)
+	}
+}
+
+// TestH2H1ProxyProtocolV1Unknown tests PROXY protocol version 1
+// containing UNKNOWN entry is accepted.
+func TestH2H1ProxyProtocolV1Unknown(t *testing.T) {
+	st := newServerTester([]string{"--accept-proxy-protocol", "--add-x-forwarded-for"}, t, func(w http.ResponseWriter, r *http.Request) {
+		if got, notWant := r.Header.Get("X-Forwarded-For"), "192.168.0.2"; got == notWant {
+			t.Errorf("X-Forwarded-For: %v")
+		}
+	})
+	defer st.Close()
+
+	st.conn.Write([]byte("PROXY UNKNOWN 192.168.0.2 192.168.0.100 12345 8080\r\n"))
+
+	res, err := st.http2(requestParam{
+		name: "TestH2H1ProxyProtocolV1Unknown",
+	})
+
+	if err != nil {
+		t.Fatalf("Error st.http2() = %v", err)
+	}
+
+	if got, want := res.status, 200; got != want {
+		t.Errorf("res.status: %v; want %v", got, want)
+	}
+}
+
+// TestH2H1ProxyProtocolV1JustUnknown tests PROXY protocol version 1
+// containing only "PROXY UNKNOWN" is accepted.
+func TestH2H1ProxyProtocolV1JustUnknown(t *testing.T) {
+	st := newServerTester([]string{"--accept-proxy-protocol", "--add-x-forwarded-for"}, t, noopHandler)
+	defer st.Close()
+
+	st.conn.Write([]byte("PROXY UNKNOWN\r\n"))
+
+	res, err := st.http2(requestParam{
+		name: "TestH2H1ProxyProtocolV1JustUnknown",
+	})
+
+	if err != nil {
+		t.Fatalf("Error st.http2() = %v", err)
+	}
+
+	if got, want := res.status, 200; got != want {
+		t.Errorf("res.status: %v; want %v", got, want)
+	}
+}
+
+// TestH2H1ProxyProtocolV1TooLongLine tests PROXY protocol version 1
+// line longer than 107 bytes must be rejected
+func TestH2H1ProxyProtocolV1TooLongLine(t *testing.T) {
+	st := newServerTester([]string{"--accept-proxy-protocol", "--add-x-forwarded-for"}, t, noopHandler)
+	defer st.Close()
+
+	st.conn.Write([]byte("PROXY UNKNOWN ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff 65535 655350\r\n"))
+
+	_, err := st.http2(requestParam{
+		name: "TestH2H1ProxyProtocolV1TooLongLine",
+	})
+
+	if err == nil {
+		t.Fatalf("connection was not terminated")
+	}
+}
+
+// TestH2H1ProxyProtocolV1BadLineEnd tests that PROXY protocol version
+// 1 line ending without \r\n should be rejected.
+func TestH2H1ProxyProtocolV1BadLineEnd(t *testing.T) {
+	st := newServerTester([]string{"--accept-proxy-protocol"}, t, noopHandler)
+	defer st.Close()
+
+	st.conn.Write([]byte("PROXY TCP6 ::1 ::1 12345 8080\r \n"))
+
+	_, err := st.http2(requestParam{
+		name: "TestH2H1ProxyProtocolV1BadLineEnd",
+	})
+
+	if err == nil {
+		t.Fatalf("connection was not terminated")
+	}
+}
+
+// TestH2H1ProxyProtocolV1NoEnd tests that PROXY protocol version 1
+// line containing no \r\n should be rejected.
+func TestH2H1ProxyProtocolV1NoEnd(t *testing.T) {
+	st := newServerTester([]string{"--accept-proxy-protocol"}, t, noopHandler)
+	defer st.Close()
+
+	st.conn.Write([]byte("PROXY TCP6 ::1 ::1 12345 8080"))
+
+	_, err := st.http2(requestParam{
+		name: "TestH2H1ProxyProtocolV1NoEnd",
+	})
+
+	if err == nil {
+		t.Fatalf("connection was not terminated")
+	}
+}
+
+// TestH2H1ProxyProtocolV1EmbeddedNULL tests that PROXY protocol
+// version 1 line containing NULL character should be rejected.
+func TestH2H1ProxyProtocolV1EmbeddedNULL(t *testing.T) {
+	st := newServerTester([]string{"--accept-proxy-protocol"}, t, noopHandler)
+	defer st.Close()
+
+	b := []byte("PROXY TCP6 ::1*foo ::1 12345 8080\r\n")
+	b[14] = 0
+	st.conn.Write(b)
+
+	_, err := st.http2(requestParam{
+		name: "TestH2H1ProxyProtocolV1EmbeddedNULL",
+	})
+
+	if err == nil {
+		t.Fatalf("connection was not terminated")
+	}
+}
+
+// TestH2H1ProxyProtocolV1MissingSrcPort tests that PROXY protocol
+// version 1 line without src port should be rejected.
+func TestH2H1ProxyProtocolV1MissingSrcPort(t *testing.T) {
+	st := newServerTester([]string{"--accept-proxy-protocol"}, t, noopHandler)
+	defer st.Close()
+
+	st.conn.Write([]byte("PROXY TCP6 ::1 ::1  8080\r\n"))
+
+	_, err := st.http2(requestParam{
+		name: "TestH2H1ProxyProtocolV1MissingSrcPort",
+	})
+
+	if err == nil {
+		t.Fatalf("connection was not terminated")
+	}
+}
+
+// TestH2H1ProxyProtocolV1MissingDstPort tests that PROXY protocol
+// version 1 line without dst port should be rejected.
+func TestH2H1ProxyProtocolV1MissingDstPort(t *testing.T) {
+	st := newServerTester([]string{"--accept-proxy-protocol"}, t, noopHandler)
+	defer st.Close()
+
+	st.conn.Write([]byte("PROXY TCP6 ::1 ::1 12345 \r\n"))
+
+	_, err := st.http2(requestParam{
+		name: "TestH2H1ProxyProtocolV1MissingDstPort",
+	})
+
+	if err == nil {
+		t.Fatalf("connection was not terminated")
+	}
+}
+
+// TestH2H1ProxyProtocolV1InvalidSrcPort tests that PROXY protocol
+// containing invalid src port should be rejected.
+func TestH2H1ProxyProtocolV1InvalidSrcPort(t *testing.T) {
+	st := newServerTester([]string{"--accept-proxy-protocol"}, t, noopHandler)
+	defer st.Close()
+
+	st.conn.Write([]byte("PROXY TCP6 ::1 ::1 123x 8080\r\n"))
+
+	_, err := st.http2(requestParam{
+		name: "TestH2H1ProxyProtocolV1InvalidSrcPort",
+	})
+
+	if err == nil {
+		t.Fatalf("connection was not terminated")
+	}
+}
+
+// TestH2H1ProxyProtocolV1InvalidDstPort tests that PROXY protocol
+// containing invalid dst port should be rejected.
+func TestH2H1ProxyProtocolV1InvalidDstPort(t *testing.T) {
+	st := newServerTester([]string{"--accept-proxy-protocol"}, t, noopHandler)
+	defer st.Close()
+
+	st.conn.Write([]byte("PROXY TCP6 ::1 ::1 123456 80x\r\n"))
+
+	_, err := st.http2(requestParam{
+		name: "TestH2H1ProxyProtocolV1InvalidDstPort",
+	})
+
+	if err == nil {
+		t.Fatalf("connection was not terminated")
+	}
+}
+
+// TestH2H1ProxyProtocolV1LeadingZeroPort tests that PROXY protocol
+// version 1 line with non zero port with leading zero should be
+// rejected.
+func TestH2H1ProxyProtocolV1LeadingZeroPort(t *testing.T) {
+	st := newServerTester([]string{"--accept-proxy-protocol"}, t, noopHandler)
+	defer st.Close()
+
+	st.conn.Write([]byte("PROXY TCP6 ::1 ::1 03000 8080\r\n"))
+
+	_, err := st.http2(requestParam{
+		name: "TestH2H1ProxyProtocolV1LeadingZeroPort",
+	})
+
+	if err == nil {
+		t.Fatalf("connection was not terminated")
+	}
+}
+
+// TestH2H1ProxyProtocolV1TooLargeSrcPort tests that PROXY protocol
+// containing too large src port should be rejected.
+func TestH2H1ProxyProtocolV1TooLargeSrcPort(t *testing.T) {
+	st := newServerTester([]string{"--accept-proxy-protocol"}, t, noopHandler)
+	defer st.Close()
+
+	st.conn.Write([]byte("PROXY TCP6 ::1 ::1 65536 8080\r\n"))
+
+	_, err := st.http2(requestParam{
+		name: "TestH2H1ProxyProtocolV1TooLargeSrcPort",
+	})
+
+	if err == nil {
+		t.Fatalf("connection was not terminated")
+	}
+}
+
+// TestH2H1ProxyProtocolV1TooLargeDstPort tests that PROXY protocol
+// containing too large dst port should be rejected.
+func TestH2H1ProxyProtocolV1TooLargeDstPort(t *testing.T) {
+	st := newServerTester([]string{"--accept-proxy-protocol"}, t, noopHandler)
+	defer st.Close()
+
+	st.conn.Write([]byte("PROXY TCP6 ::1 ::1 12345 65536\r\n"))
+
+	_, err := st.http2(requestParam{
+		name: "TestH2H1ProxyProtocolV1TooLargeDstPort",
+	})
+
+	if err == nil {
+		t.Fatalf("connection was not terminated")
+	}
+}
+
+// TestH2H1ProxyProtocolV1InvalidSrcAddr tests that PROXY protocol
+// containing invalid src addr should be rejected.
+func TestH2H1ProxyProtocolV1InvalidSrcAddr(t *testing.T) {
+	st := newServerTester([]string{"--accept-proxy-protocol"}, t, noopHandler)
+	defer st.Close()
+
+	st.conn.Write([]byte("PROXY TCP6 192.168.0.1 ::1 12345 8080\r\n"))
+
+	_, err := st.http2(requestParam{
+		name: "TestH2H1ProxyProtocolV1InvalidSrcAddr",
+	})
+
+	if err == nil {
+		t.Fatalf("connection was not terminated")
+	}
+}
+
+// TestH2H1ProxyProtocolV1InvalidDstAddr tests that PROXY protocol
+// containing invalid dst addr should be rejected.
+func TestH2H1ProxyProtocolV1InvalidDstAddr(t *testing.T) {
+	st := newServerTester([]string{"--accept-proxy-protocol"}, t, noopHandler)
+	defer st.Close()
+
+	st.conn.Write([]byte("PROXY TCP6 ::1 192.168.0.1 12345 8080\r\n"))
+
+	_, err := st.http2(requestParam{
+		name: "TestH2H1ProxyProtocolV1InvalidDstAddr",
+	})
+
+	if err == nil {
+		t.Fatalf("connection was not terminated")
+	}
+}
+
+// TestH2H1ProxyProtocolV1InvalidProtoFamily tests that PROXY protocol
+// containing invalid protocol family should be rejected.
+func TestH2H1ProxyProtocolV1InvalidProtoFamily(t *testing.T) {
+	st := newServerTester([]string{"--accept-proxy-protocol"}, t, noopHandler)
+	defer st.Close()
+
+	st.conn.Write([]byte("PROXY UNIX ::1 ::1 12345 8080\r\n"))
+
+	_, err := st.http2(requestParam{
+		name: "TestH2H1ProxyProtocolV1InvalidProtoFamily",
+	})
+
+	if err == nil {
+		t.Fatalf("connection was not terminated")
+	}
+}
+
+// TestH2H1ProxyProtocolV1InvalidID tests that PROXY protocol
+// containing invalid PROXY protocol version 1 ID should be rejected.
+func TestH2H1ProxyProtocolV1InvalidID(t *testing.T) {
+	st := newServerTester([]string{"--accept-proxy-protocol"}, t, noopHandler)
+	defer st.Close()
+
+	st.conn.Write([]byte("PR0XY TCP6 ::1 ::1 12345 8080\r\n"))
+
+	_, err := st.http2(requestParam{
+		name: "TestH2H1ProxyProtocolV1InvalidID",
+	})
+
+	if err == nil {
+		t.Fatalf("connection was not terminated")
+	}
+}
+
 // TestH2H1GracefulShutdown tests graceful shutdown.
 func TestH2H1GracefulShutdown(t *testing.T) {
 	st := newServerTester(nil, t, noopHandler)
diff --git a/src/shrpx.cc b/src/shrpx.cc
index 9aac0cde..9354a14f 100644
--- a/src/shrpx.cc
+++ b/src/shrpx.cc
@@ -1268,6 +1268,8 @@ Connections:
               timeouts when connecting and  making CONNECT request can
               be     specified    by     --backend-read-timeout    and
               --backend-write-timeout options.
+  --accept-proxy-protocol
+              Accept PROXY protocol version 1 on frontend connection.
 
 Performance:
   -n, --workers=<N>
@@ -1915,6 +1917,7 @@ int main(int argc, char **argv) {
          90},
         {SHRPX_OPT_REQUEST_PHASE_FILE, required_argument, &flag, 91},
         {SHRPX_OPT_RESPONSE_PHASE_FILE, required_argument, &flag, 92},
+        {SHRPX_OPT_ACCEPT_PROXY_PROTOCOL, no_argument, &flag, 93},
         {nullptr, 0, nullptr, 0}};
 
     int option_index = 0;
@@ -2316,6 +2319,10 @@ int main(int argc, char **argv) {
         // --response-phase-file
         cmdcfgs.emplace_back(SHRPX_OPT_RESPONSE_PHASE_FILE, optarg);
         break;
+      case 93:
+        // --accept-proxy-protocol
+        cmdcfgs.emplace_back(SHRPX_OPT_ACCEPT_PROXY_PROTOCOL, "yes");
+        break;
       default:
         break;
       }
diff --git a/src/shrpx_client_handler.cc b/src/shrpx_client_handler.cc
index 87c1659e..f7602dac 100644
--- a/src/shrpx_client_handler.cc
+++ b/src/shrpx_client_handler.cc
@@ -104,6 +104,8 @@ void writecb(struct ev_loop *loop, ev_io *w, int revents) {
 }
 } // namespace
 
+int ClientHandler::noop() { return 0; }
+
 int ClientHandler::read_clear() {
   ev_timer_again(conn_.loop, &conn_.rt);
 
@@ -382,6 +384,17 @@ ClientHandler::ClientHandler(Worker *worker, int fd, SSL *ssl,
   conn_.rlimit.startw();
   ev_timer_again(conn_.loop, &conn_.rt);
 
+  if (get_config()->accept_proxy_protocol) {
+    read_ = &ClientHandler::read_clear;
+    write_ = &ClientHandler::noop;
+    on_read_ = &ClientHandler::proxy_protocol_read;
+    on_write_ = &ClientHandler::upstream_noop;
+  } else {
+    setup_upstream_io_callback();
+  }
+}
+
+void ClientHandler::setup_upstream_io_callback() {
   if (conn_.tls.ssl) {
     conn_.prepare_server_handshake();
     read_ = write_ = &ClientHandler::tls_handshake;
@@ -829,4 +842,235 @@ ev_io *ClientHandler::get_wev() { return &conn_.wev; }
 
 Worker *ClientHandler::get_worker() const { return worker_; }
 
+namespace {
+ssize_t parse_proxy_line_port(const uint8_t *first, const uint8_t *last) {
+  auto p = first;
+  int32_t port = 0;
+
+  if (p == last) {
+    return -1;
+  }
+
+  if (*p == '0') {
+    if (p + 1 != last && util::isDigit(*(p + 1))) {
+      return -1;
+    }
+    return 1;
+  }
+
+  for (; p != last && util::isDigit(*p); ++p) {
+    port *= 10;
+    port += *p - '0';
+
+    if (port > 65535) {
+      return -1;
+    }
+  }
+
+  return p - first;
+}
+} // namespace
+
+int ClientHandler::on_proxy_protocol_finish() {
+  setup_upstream_io_callback();
+
+  // Run on_read to process data left in buffer since they are not
+  // notified further
+  if (on_read() != 0) {
+    return -1;
+  }
+
+  return 0;
+}
+
+// http://www.haproxy.org/download/1.5/doc/proxy-protocol.txt
+int ClientHandler::proxy_protocol_read() {
+  if (LOG_ENABLED(INFO)) {
+    CLOG(INFO, this) << "PROXY-protocol: Started";
+  }
+
+  auto first = rb_.pos;
+
+  // NULL character really destroys functions which expects NULL
+  // terminated string.  We won't expect it in PROXY protocol line, so
+  // find it here.
+  auto chrs = std::array<char, 2>{{'\n', '\0'}};
+
+  constexpr size_t MAX_PROXY_LINELEN = 107;
+
+  auto bufend = rb_.pos + std::min(MAX_PROXY_LINELEN, rb_.rleft());
+
+  auto end =
+      std::find_first_of(rb_.pos, bufend, std::begin(chrs), std::end(chrs));
+
+  if (end == bufend) {
+    if (rb_.rleft() >= MAX_PROXY_LINELEN) {
+      if (LOG_ENABLED(INFO)) {
+        CLOG(INFO, this) << "PROXY-protocol-v1: No ending CR LF sequence found";
+      }
+      return -1;
+    }
+    return 0;
+  }
+
+  if (*end == '\0' || end == rb_.pos || *(end - 1) != '\r') {
+    if (LOG_ENABLED(INFO)) {
+      CLOG(INFO, this) << "PROXY-protocol-v1: No ending CR LF sequence found";
+    }
+    return -1;
+  }
+
+  --end;
+
+  constexpr const char HEADER[] = "PROXY ";
+
+  if (end - rb_.pos < str_size(HEADER)) {
+    if (LOG_ENABLED(INFO)) {
+      CLOG(INFO, this) << "PROXY-protocol-v1: PROXY version 1 ID not found";
+    }
+    return -1;
+  }
+
+  if (!util::streq_l(HEADER, rb_.pos, str_size(HEADER))) {
+    if (LOG_ENABLED(INFO)) {
+      CLOG(INFO, this) << "PROXY-protocol-v1: Bad PROXY protocol version 1 ID";
+    }
+    return -1;
+  }
+
+  rb_.drain(str_size(HEADER));
+
+  int family;
+
+  if (rb_.pos[0] == 'T') {
+    if (end - rb_.pos < 5) {
+      if (LOG_ENABLED(INFO)) {
+        CLOG(INFO, this) << "PROXY-protocol-v1: INET protocol family not found";
+      }
+      return -1;
+    }
+
+    if (rb_.pos[1] != 'C' || rb_.pos[2] != 'P') {
+      if (LOG_ENABLED(INFO)) {
+        CLOG(INFO, this) << "PROXY-protocol-v1: Unknown INET protocol family";
+      }
+      return -1;
+    }
+
+    switch (rb_.pos[3]) {
+    case '4':
+      family = AF_INET;
+      break;
+    case '6':
+      family = AF_INET6;
+      break;
+    default:
+      if (LOG_ENABLED(INFO)) {
+        CLOG(INFO, this) << "PROXY-protocol-v1: Unknown INET protocol family";
+      }
+      return -1;
+    }
+
+    rb_.drain(5);
+  } else {
+    if (end - rb_.pos < 7) {
+      if (LOG_ENABLED(INFO)) {
+        CLOG(INFO, this) << "PROXY-protocol-v1: INET protocol family not found";
+      }
+      return -1;
+    }
+    if (!util::streq_l("UNKNOWN", rb_.pos, 7)) {
+      if (LOG_ENABLED(INFO)) {
+        CLOG(INFO, this) << "PROXY-protocol-v1: Unknown INET protocol family";
+      }
+      return -1;
+    }
+
+    rb_.drain(end + 2 - rb_.pos);
+
+    return on_proxy_protocol_finish();
+  }
+
+  // source address
+  auto token_end = std::find(rb_.pos, end, ' ');
+  if (token_end == end) {
+    if (LOG_ENABLED(INFO)) {
+      CLOG(INFO, this) << "PROXY-protocol-v1: Source address not found";
+    }
+    return -1;
+  }
+
+  *token_end = '\0';
+  if (!util::numeric_host(reinterpret_cast<const char *>(rb_.pos), family)) {
+    if (LOG_ENABLED(INFO)) {
+      CLOG(INFO, this) << "PROXY-protocol-v1: Invalid source address";
+    }
+    return -1;
+  }
+
+  auto src_addr = rb_.pos;
+  auto src_addrlen = token_end - rb_.pos;
+
+  rb_.drain(token_end - rb_.pos + 1);
+
+  // destination address
+  token_end = std::find(rb_.pos, end, ' ');
+  if (token_end == end) {
+    if (LOG_ENABLED(INFO)) {
+      CLOG(INFO, this) << "PROXY-protocol-v1: Destination address not found";
+    }
+    return -1;
+  }
+
+  *token_end = '\0';
+  if (!util::numeric_host(reinterpret_cast<const char *>(rb_.pos), family)) {
+    if (LOG_ENABLED(INFO)) {
+      CLOG(INFO, this) << "PROXY-protocol-v1: Invalid destination address";
+    }
+    return -1;
+  }
+
+  // Currently we don't use destination address
+
+  rb_.drain(token_end - rb_.pos + 1);
+
+  // source port
+  auto n = parse_proxy_line_port(rb_.pos, end);
+  if (n <= 0 || *(rb_.pos + n) != ' ') {
+    if (LOG_ENABLED(INFO)) {
+      CLOG(INFO, this) << "PROXY-protocol-v1: Invalid source port";
+    }
+    return -1;
+  }
+
+  rb_.pos[n] = '\0';
+  auto src_port = rb_.pos;
+  auto src_portlen = n;
+
+  rb_.drain(n + 1);
+
+  // destination  port
+  n = parse_proxy_line_port(rb_.pos, end);
+  if (n <= 0 || rb_.pos + n != end) {
+    if (LOG_ENABLED(INFO)) {
+      CLOG(INFO, this) << "PROXY-protocol-v1: Invalid destination port";
+    }
+    return -1;
+  }
+
+  // Currently we don't use destination port
+
+  rb_.drain(end + 2 - rb_.pos);
+
+  ipaddr_.assign(src_addr, src_addr + src_addrlen);
+  port_.assign(src_port, src_port + src_portlen);
+
+  if (LOG_ENABLED(INFO)) {
+    CLOG(INFO, this) << "PROXY-protocol-v1: Finished, " << (rb_.pos - first)
+                     << " bytes read";
+  }
+
+  return on_proxy_protocol_finish();
+}
+
 } // namespace shrpx
diff --git a/src/shrpx_client_handler.h b/src/shrpx_client_handler.h
index 4d4ccd9c..b9931301 100644
--- a/src/shrpx_client_handler.h
+++ b/src/shrpx_client_handler.h
@@ -56,6 +56,7 @@ public:
                 const char *port);
   ~ClientHandler();
 
+  int noop();
   // Performs clear text I/O
   int read_clear();
   int write_clear();
@@ -71,6 +72,9 @@ public:
   int upstream_http1_connhd_read();
   int upstream_write();
 
+  int proxy_protocol_read();
+  int on_proxy_protocol_finish();
+
   // Performs I/O operation.  Internally calls on_read()/on_write().
   int do_read();
   int do_write();
@@ -130,6 +134,8 @@ public:
   void signal_write();
   ev_io *get_wev();
 
+  void setup_upstream_io_callback();
+
 private:
   Connection conn_;
   ev_timer reneg_shutdown_timer_;
diff --git a/src/shrpx_config.cc b/src/shrpx_config.cc
index ce2927b7..fb2d34ef 100644
--- a/src/shrpx_config.cc
+++ b/src/shrpx_config.cc
@@ -625,6 +625,7 @@ void parse_mapping(const DownstreamAddr &addr, const char *src) {
 
 // generated by gennghttpxfun.py
 enum {
+  SHRPX_OPTID_ACCEPT_PROXY_PROTOCOL,
   SHRPX_OPTID_ACCESSLOG_FILE,
   SHRPX_OPTID_ACCESSLOG_FORMAT,
   SHRPX_OPTID_ACCESSLOG_SYSLOG,
@@ -1099,6 +1100,11 @@ int option_lookup_token(const char *name, size_t namelen) {
         return SHRPX_OPTID_BACKEND_TLS_SNI_FIELD;
       }
       break;
+    case 'l':
+      if (util::strieq_l("accept-proxy-protoco", name, 20)) {
+        return SHRPX_OPTID_ACCEPT_PROXY_PROTOCOL;
+      }
+      break;
     case 'r':
       if (util::strieq_l("tls-ticket-key-ciphe", name, 20)) {
         return SHRPX_OPTID_TLS_TICKET_KEY_CIPHER;
@@ -1968,6 +1974,10 @@ int parse_config(const char *opt, const char *optarg,
     LOG(WARN) << opt
               << ": ignored because mruby support is disabled at build time.";
 #endif // !HAVE_MRUBY
+    return 0;
+  case SHRPX_OPTID_ACCEPT_PROXY_PROTOCOL:
+    mod_config()->accept_proxy_protocol = util::strieq(optarg, "yes");
+
     return 0;
   case SHRPX_OPTID_CONF:
     LOG(WARN) << "conf: ignored";
diff --git a/src/shrpx_config.h b/src/shrpx_config.h
index 2bbb9647..3da46dee 100644
--- a/src/shrpx_config.h
+++ b/src/shrpx_config.h
@@ -185,6 +185,7 @@ constexpr char SHRPX_OPT_TLS_TICKET_KEY_MEMCACHED_MAX_FAIL[] =
     "tls-ticket-key-memcached-max-fail";
 constexpr char SHRPX_OPT_REQUEST_PHASE_FILE[] = "request-phase-file";
 constexpr char SHRPX_OPT_RESPONSE_PHASE_FILE[] = "response-phase-file";
+constexpr char SHRPX_OPT_ACCEPT_PROXY_PROTOCOL[] = "accept-proxy-protocol";
 
 union sockaddr_union {
   sockaddr_storage storage;
@@ -409,6 +410,7 @@ struct Config {
   bool no_ocsp;
   // true if --tls-ticket-key-cipher is used
   bool tls_ticket_key_cipher_given;
+  bool accept_proxy_protocol;
 };
 
 const Config *get_config();
diff --git a/src/util.cc b/src/util.cc
index 857a848e..d3699aab 100644
--- a/src/util.cc
+++ b/src/util.cc
@@ -626,15 +626,16 @@ void write_uri_field(std::ostream &o, const char *uri, const http_parser_url &u,
 }
 
 bool numeric_host(const char *hostname) {
-  struct addrinfo *res;
-  struct addrinfo hints {};
-  hints.ai_family = AF_UNSPEC;
-  hints.ai_flags = AI_NUMERICHOST;
-  if (getaddrinfo(hostname, nullptr, &hints, &res)) {
-    return false;
-  }
-  freeaddrinfo(res);
-  return true;
+  return numeric_host(hostname, AF_INET) || numeric_host(hostname, AF_INET6);
+}
+
+bool numeric_host(const char *hostname, int family) {
+  int rv;
+  std::array<uint8_t, sizeof(struct in6_addr)> dst;
+
+  rv = inet_pton(family, hostname, dst.data());
+
+  return rv == 1;
 }
 
 std::string numeric_name(const struct sockaddr *sa, socklen_t salen) {
diff --git a/src/util.h b/src/util.h
index 7524a247..877ddc22 100644
--- a/src/util.h
+++ b/src/util.h
@@ -516,6 +516,8 @@ void write_uri_field(std::ostream &o, const char *uri, const http_parser_url &u,
 
 bool numeric_host(const char *hostname);
 
+bool numeric_host(const char *hostname, int family);
+
 // Returns numeric address string of |addr|.  If getnameinfo() is
 // failed, "unknown" is returned.
 std::string numeric_name(const struct sockaddr *sa, socklen_t salen);