diff --git a/openssl-sys/src/lib.rs b/openssl-sys/src/lib.rs
index 9b5fd744773f9f144e1d23065ff13a1c8013916c..91b090e2c1004702c5795c6376975d5925645c87 100644
--- a/openssl-sys/src/lib.rs
+++ b/openssl-sys/src/lib.rs
@@ -167,11 +167,11 @@ macro_rules! import_options {
 
 include!("ssl_options.rs");
 
-#[cfg(feature = "npn")]
+#[cfg(any(feature = "npn", feature = "alpn"))]
 pub const OPENSSL_NPN_UNSUPPORTED: c_int = 0;
-#[cfg(feature = "npn")]
+#[cfg(any(feature = "npn", feature = "alpn"))]
 pub const OPENSSL_NPN_NEGOTIATED: c_int = 1;
-#[cfg(feature = "npn")]
+#[cfg(any(feature = "npn", feature = "alpn"))]
 pub const OPENSSL_NPN_NO_OVERLAP: c_int = 2;
 
 pub const V_ASN1_GENERALIZEDTIME: c_int = 24;
diff --git a/openssl/src/ssl/mod.rs b/openssl/src/ssl/mod.rs
index ee2e1f9f865de078a4f9a1fb349378798e368c11..1f198643b2021652fce6382cc4c4ececa0282073 100644
--- a/openssl/src/ssl/mod.rs
+++ b/openssl/src/ssl/mod.rs
@@ -308,8 +308,11 @@ unsafe fn select_proto_using(ssl: *mut ffi::SSL,
         let client_len = protocols.len() as c_uint;
         // Finally, let OpenSSL find a protocol to be used, by matching the given server and
         // client lists.
-        ffi::SSL_select_next_proto(out, outlen, inbuf, inlen, client, client_len);
-        ffi::SSL_TLSEXT_ERR_OK
+        if ffi::SSL_select_next_proto(out, outlen, inbuf, inlen, client, client_len) != ffi::OPENSSL_NPN_NEGOTIATED {
+            ffi::SSL_TLSEXT_ERR_NOACK
+        } else {
+            ffi::SSL_TLSEXT_ERR_OK
+        }
 }
 
 /// The function is given as the callback to `SSL_CTX_set_next_proto_select_cb`.