diff --git a/src/socket.rs b/src/socket.rs
index 0c8d4997..af493f70 100644
--- a/src/socket.rs
+++ b/src/socket.rs
@@ -1640,7 +1640,6 @@ impl Socket {
         target_os = "fuchsia",
         target_os = "redox",
         target_os = "solaris",
-        target_os = "illumos",
         target_os = "haiku",
         target_os = "wasi",
     )))]
@@ -1660,7 +1659,6 @@ impl Socket {
         target_os = "fuchsia",
         target_os = "redox",
         target_os = "solaris",
-        target_os = "illumos",
         target_os = "haiku",
         target_os = "wasi",
     )))]
diff --git a/src/sys/unix.rs b/src/sys/unix.rs
index 9a1b6e87..da6adc8c 100644
--- a/src/sys/unix.rs
+++ b/src/sys/unix.rs
@@ -209,7 +209,6 @@ pub(crate) use libc::IP_RECVTOS;
     target_os = "redox",
     target_os = "solaris",
     target_os = "haiku",
-    target_os = "illumos",
     target_os = "wasi",
 )))]
 pub(crate) use libc::IP_TOS;
@@ -2643,6 +2642,7 @@ impl crate::Socket {
             target_os = "netbsd",
             target_os = "openbsd",
             target_os = "cygwin",
+            target_os = "illumos",
         )
     ))]
     pub fn tclass_v6(&self) -> io::Result<u32> {
@@ -2668,6 +2668,7 @@ impl crate::Socket {
             target_os = "netbsd",
             target_os = "openbsd",
             target_os = "cygwin",
+            target_os = "illumos",
         )
     ))]
     pub fn set_tclass_v6(&self, tclass: u32) -> io::Result<()> {
diff --git a/tests/socket.rs b/tests/socket.rs
index 6dc1aea0..886a8eab 100644
--- a/tests/socket.rs
+++ b/tests/socket.rs
@@ -1523,7 +1523,6 @@ test!(IPv4 ttl_v4, set_ttl_v4(40));
     target_os = "fuchsia",
     target_os = "redox",
     target_os = "solaris",
-    target_os = "illumos",
     target_os = "haiku",
     target_os = "cygwin",
     target_os = "wasi",
@@ -1577,7 +1576,8 @@ test!(IPv6 only_v6, set_only_v6(false));
         target_os = "linux",
         target_os = "macos",
         target_os = "netbsd",
-        target_os = "openbsd"
+        target_os = "openbsd",
+        target_os = "illumos"
     )
 ))]
 test!(IPv6 tclass_v6, set_tclass_v6(96));