diff --git a/.github/workflows/ci_test_freebsd.yml b/.github/workflows/ci_test_freebsd.yml
index 55259b3f..1474a291 100644
--- a/.github/workflows/ci_test_freebsd.yml
+++ b/.github/workflows/ci_test_freebsd.yml
@@ -12,9 +12,6 @@ concurrency:
   group: ${{ github.workflow }}-${{ github.ref }}-${{ github.event_name }}
   cancel-in-progress: true
 
-env:
-  RUST_BACKTRACE: 1
-
 jobs:
   test:
     runs-on: ubuntu-latest
@@ -46,4 +43,4 @@ jobs:
                 ARGS="$ARGS --features nightly"
             fi
 
-            cargo +${{ matrix.toolchain }} test --workspace $ARGS
+            RUST_BACKTRACE=1 cargo +${{ matrix.toolchain }} test --workspace $ARGS
diff --git a/.github/workflows/ci_test_illumos.yml b/.github/workflows/ci_test_illumos.yml
new file mode 100644
index 00000000..a996fac1
--- /dev/null
+++ b/.github/workflows/ci_test_illumos.yml
@@ -0,0 +1,46 @@
+name: TestIllumos
+
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+    branches:
+      - master
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}-${{ github.event_name }}
+  cancel-in-progress: true
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        toolchain: ["nightly", "beta", "stable"]
+    steps:
+      - uses: actions/checkout@v4
+      - name: Test in Illumos
+        id: test
+        uses: vmactions/omnios-vm@v1
+        with:
+          usesh: true
+          sync: rsync
+          copyback: false
+          prepare: |
+            pkg install gcc14 curl pkg-config glib2
+            curl --proto '=https' --tlsv1.2 https://sh.rustup.rs -sSf > install.sh
+            chmod +x install.sh
+            ./install.sh -y --default-toolchain ${{ matrix.toolchain }} --profile minimal
+          run: |
+            . "$HOME/.cargo/env"
+            set -ex
+
+            ARGS="--features all"
+
+            # Add feature "nightly" if toolchain is nightly
+            if [ "${{ matrix.toolchain }}" = "nightly" ]; then
+                ARGS="$ARGS --features nightly"
+            fi
+
+            RUST_BACKTRACE=1 cargo +${{ matrix.toolchain }} test --workspace $ARGS
diff --git a/compio-quic/Cargo.toml b/compio-quic/Cargo.toml
index bceb11ce..ce860372 100644
--- a/compio-quic/Cargo.toml
+++ b/compio-quic/Cargo.toml
@@ -51,13 +51,15 @@ compio-runtime = { workspace = true, features = ["criterion"] }
 
 criterion = { workspace = true, features = ["async_tokio"] }
 http = "1.1.0"
-quinn = "0.11.5"
 rand = { workspace = true }
 rcgen = "0.13.1"
 socket2 = { workspace = true, features = ["all"] }
 tokio = { workspace = true, features = ["rt", "macros"] }
 tracing-subscriber = { workspace = true, features = ["env-filter"] }
 
+[target.'cfg(not(any(target_os = "illumos", target_os = "solaris")))'.dev-dependencies]
+quinn = "0.11.5"
+
 [features]
 default = []
 io-compat = ["futures-util/io"]
diff --git a/compio-quic/benches/quic.rs b/compio-quic/benches/quic.rs
index 106d27e2..24c7681c 100644
--- a/compio-quic/benches/quic.rs
+++ b/compio-quic/benches/quic.rs
@@ -1,7 +1,8 @@
+use std::time::Instant;
+#[cfg(not(any(target_os = "illumos", target_os = "solaris")))]
 use std::{
     net::{IpAddr, Ipv4Addr, SocketAddr},
     sync::Arc,
-    time::Instant,
 };
 
 use compio_buf::bytes::Bytes;
@@ -104,6 +105,7 @@ fn echo_compio_quic(b: &mut Bencher, content: &[u8], streams: usize) {
     })
 }
 
+#[cfg(not(any(target_os = "illumos", target_os = "solaris")))]
 fn echo_quinn(b: &mut Bencher, content: &[u8], streams: usize) {
     use quinn::{ClientConfig, Endpoint, ServerConfig};
 
@@ -182,6 +184,7 @@ fn echo(c: &mut Criterion) {
                 &(),
                 |b, _| echo_compio_quic(b, data, streams),
             );
+            #[cfg(not(any(target_os = "illumos", target_os = "solaris")))]
             group.bench_with_input(
                 BenchmarkId::new("quinn", format!("{}-streams-{}-bytes", streams, size)),
                 &(),
diff --git a/compio-quic/src/socket.rs b/compio-quic/src/socket.rs
index 163923d8..1537d104 100644
--- a/compio-quic/src/socket.rs
+++ b/compio-quic/src/socket.rs
@@ -196,7 +196,15 @@ impl Socket {
 
         // ECN
         if is_ipv4 {
-            #[cfg(all(unix, not(any(target_os = "openbsd", target_os = "netbsd"))))]
+            #[cfg(all(
+                unix,
+                not(any(
+                    target_os = "openbsd",
+                    target_os = "netbsd",
+                    target_os = "illumos",
+                    target_os = "solaris"
+                ))
+            ))]
             set_socket_option!(socket, libc::IPPROTO_IP, libc::IP_RECVTOS, &1);
             #[cfg(windows)]
             set_socket_option!(socket, WinSock::IPPROTO_IP, WinSock::IP_ECN, &1);
@@ -216,6 +224,8 @@ impl Socket {
                 target_os = "freebsd",
                 target_os = "openbsd",
                 target_os = "netbsd",
+                target_os = "illumos",
+                target_os = "solaris",
                 target_os = "macos",
                 target_os = "ios"
             ))]
@@ -364,7 +374,15 @@ impl Socket {
                     // ECN
                     #[cfg(unix)]
                     (libc::IPPROTO_IP, libc::IP_TOS) => ecn_bits = *cmsg.data::<u8>(),
-                    #[cfg(all(unix, not(any(target_os = "openbsd", target_os = "netbsd"))))]
+                    #[cfg(all(
+                        unix,
+                        not(any(
+                            target_os = "openbsd",
+                            target_os = "netbsd",
+                            target_os = "illumos",
+                            target_os = "solaris"
+                        ))
+                    ))]
                     (libc::IPPROTO_IP, libc::IP_RECVTOS) => ecn_bits = *cmsg.data::<u8>(),
                     #[cfg(unix)]
                     (libc::IPPROTO_IPV6, libc::IPV6_TCLASS) => {
@@ -387,6 +405,8 @@ impl Socket {
                         target_os = "freebsd",
                         target_os = "openbsd",
                         target_os = "netbsd",
+                        target_os = "illumos",
+                        target_os = "solaris",
                         target_os = "macos",
                         target_os = "ios",
                     ))]
@@ -474,6 +494,8 @@ impl Socket {
                     target_os = "netbsd",
                     target_os = "macos",
                     target_os = "ios",
+                    target_os = "illumos",
+                    target_os = "solaris",
                 ))]
                 {
                     #[cfg(target_os = "freebsd")]
@@ -483,6 +505,8 @@ impl Socket {
                         target_os = "netbsd",
                         target_os = "macos",
                         target_os = "ios",
+                        target_os = "illumos",
+                        target_os = "solaris",
                     ))]
                     let encode_src_ip_v4 = true;
 
@@ -678,7 +702,15 @@ mod tests {
     }
 
     #[compio_macros::test]
-    #[cfg_attr(any(target_os = "openbsd", target_os = "netbsd"), ignore)]
+    #[cfg_attr(
+        any(
+            target_os = "openbsd",
+            target_os = "netbsd",
+            target_os = "illumos",
+            target_os = "solaris"
+        ),
+        ignore
+    )]
     async fn ecn_v4() {
         let passive = Socket::new(UdpSocket::bind("127.0.0.1:0").await.unwrap()).unwrap();
         let active = Socket::new(UdpSocket::bind("127.0.0.1:0").await.unwrap()).unwrap();
@@ -740,7 +772,15 @@ mod tests {
     }
 
     #[compio_macros::test]
-    #[cfg_attr(any(target_os = "openbsd", target_os = "netbsd"), ignore)]
+    #[cfg_attr(
+        any(
+            target_os = "openbsd",
+            target_os = "netbsd",
+            target_os = "illumos",
+            target_os = "solaris"
+        ),
+        ignore
+    )]
     async fn ecn_v4_mapped_v6() {
         let passive = Socket::new(UdpSocket::bind("127.0.0.1:0").await.unwrap()).unwrap();
         let active = Socket::new(bind_udp_dualstack().unwrap()).unwrap();
diff --git a/compio-quic/tests/echo.rs b/compio-quic/tests/echo.rs
index f3a90835..fccc6a16 100644
--- a/compio-quic/tests/echo.rs
+++ b/compio-quic/tests/echo.rs
@@ -140,6 +140,8 @@ async fn echo_v4() {
         target_os = "openbsd",
         target_os = "netbsd",
         target_os = "freebsd",
+        target_os = "illumos",
+        target_os = "solaris",
         windows
     ),
     ignore