diff --git a/src/sys/unix.rs b/src/sys/unix.rs
index 0c2f7eb7..a48a0b69 100644
--- a/src/sys/unix.rs
+++ b/src/sys/unix.rs
@@ -302,7 +302,7 @@ pub(crate) type Bool = c_int;
     target_os = "ios",
     target_os = "visionos",
     target_os = "macos",
-    target_os = "nto",
+    all(target_os = "nto", any(target_env = "nto70", target_env = "nto71"),),
     target_os = "tvos",
     target_os = "watchos",
 ))]
@@ -312,7 +312,7 @@ use libc::TCP_KEEPALIVE as KEEPALIVE_TIME;
     target_os = "ios",
     target_os = "visionos",
     target_os = "macos",
-    target_os = "nto",
+    all(target_os = "nto", any(target_env = "nto70", target_env = "nto71"),),
     target_os = "openbsd",
     target_os = "tvos",
     target_os = "watchos",