diff --git a/eo-runtime/src/main/java/EOorg/EOeolang/EOsys/Posix/InetAddrSyscall.java b/eo-runtime/src/main/java/EOorg/EOeolang/EOsys/Posix/InetAddrSyscall.java
index be31d96d84..405c6a50b9 100644
--- a/eo-runtime/src/main/java/EOorg/EOeolang/EOsys/Posix/InetAddrSyscall.java
+++ b/eo-runtime/src/main/java/EOorg/EOeolang/EOsys/Posix/InetAddrSyscall.java
@@ -56,7 +56,11 @@ public Phi make(final Phi... params) {
         final Phi result = this.posix.take("return").copy();
         result.put(
             0,
-            new Data.ToPhi(CStdLib.INSTANCE.inet_addr(new Dataized(params[0]).asString()))
+            new Data.ToPhi(
+                Integer.reverseBytes(
+                    CStdLib.INSTANCE.inet_addr(new Dataized(params[0]).asString())
+                )
+            )
         );
         result.put(1, new PhDefault());
         return result;
diff --git a/eo-runtime/src/main/java/EOorg/EOeolang/EOsys/Win32/InetAddrFuncCall.java b/eo-runtime/src/main/java/EOorg/EOeolang/EOsys/Win32/InetAddrFuncCall.java
index c0df8955ed..dbec426002 100644
--- a/eo-runtime/src/main/java/EOorg/EOeolang/EOsys/Win32/InetAddrFuncCall.java
+++ b/eo-runtime/src/main/java/EOorg/EOeolang/EOsys/Win32/InetAddrFuncCall.java
@@ -59,7 +59,11 @@ public Phi make(final Phi... params) {
         final Phi result = this.win.take("return").copy();
         result.put(
             0,
-            new Data.ToPhi(Winsock.INSTANCE.inet_addr(new Dataized(params[0]).asString()))
+            new Data.ToPhi(
+                Integer.reverseBytes(
+                    Winsock.INSTANCE.inet_addr(new Dataized(params[0]).asString())
+                )
+            )
         );
         result.put(1, new PhDefault());
         return result;
diff --git a/eo-runtime/src/test/eo/org/eolang/sys/posix-tests.eo b/eo-runtime/src/test/eo/org/eolang/sys/posix-tests.eo
index 24741f1754..c999c27910 100644
--- a/eo-runtime/src/test/eo/org/eolang/sys/posix-tests.eo
+++ b/eo-runtime/src/test/eo/org/eolang/sys/posix-tests.eo
@@ -73,3 +73,13 @@
                 "close"
                 * sd
             -1
+
+# Test.
+[] > returns-valid-posix-inet-addr-for-localhost
+  code. > addr
+    posix
+      "inet_addr"
+      * "127.0.0.1"
+  or. > @
+    os.is-windows
+    addr.eq 2130706433
diff --git a/eo-runtime/src/test/eo/org/eolang/sys/win32-tests.eo b/eo-runtime/src/test/eo/org/eolang/sys/win32-tests.eo
index 38770dd231..e14ebdacff 100644
--- a/eo-runtime/src/test/eo/org/eolang/sys/win32-tests.eo
+++ b/eo-runtime/src/test/eo/org/eolang/sys/win32-tests.eo
@@ -43,3 +43,13 @@
     and.
       called.code
       called.output.eq msg.size
+
+# Test.
+[] > returns-valid-win32-inet-addr-for-localhost
+  code. > addr
+    win32
+      "inet_addr"
+      * "127.0.0.1"
+  or. > @
+    os.is-windows.not
+    addr.eq 2130706433
diff --git a/eo-runtime/src/test/java/EOorg/EOeolang/EOnet/EOsocketTest.java b/eo-runtime/src/test/java/EOorg/EOeolang/EOnet/EOsocketTest.java
index 3e127ea3d2..f0d571e3bf 100644
--- a/eo-runtime/src/test/java/EOorg/EOeolang/EOnet/EOsocketTest.java
+++ b/eo-runtime/src/test/java/EOorg/EOeolang/EOnet/EOsocketTest.java
@@ -64,7 +64,7 @@ final class EOsocketTest {
     /**
      * Localhost IP.
      */
-    private static String LOCALHOST = "127.0.0.1";
+    private static final String LOCALHOST = "127.0.0.1";
 
     @Test
     @DisabledOnOs(OS.WINDOWS)
@@ -79,7 +79,7 @@ void connectsToLocalServerViaPosixSyscall() throws IOException {
         final SockaddrIn addr = new SockaddrIn(
             (short) CStdLib.AF_INET,
             EOsocketTest.htons(8080),
-            CStdLib.INSTANCE.inet_addr(EOsocketTest.LOCALHOST)
+            Integer.reverseBytes(CStdLib.INSTANCE.inet_addr(EOsocketTest.LOCALHOST))
         );
         final int connected = CStdLib.INSTANCE.connect(socket, addr, addr.size());
         final String error;
@@ -107,7 +107,7 @@ void connectsToLocalServerViaWindowsSyscall() throws IOException {
         assert Winsock.INSTANCE.WSAStartup(
             Winsock.WINSOCK_VERSION_2_2,
             new WSAStartupFuncCall.WSAData()
-        ) > 0;
+        ) == 0;
         final int socket = Winsock.INSTANCE.socket(
             Winsock.AF_INET,
             Winsock.SOCK_STREAM,
@@ -117,7 +117,7 @@ void connectsToLocalServerViaWindowsSyscall() throws IOException {
         final SockaddrIn addr = new SockaddrIn(
             (short) Winsock.AF_INET,
             EOsocketTest.htons(8080),
-            Winsock.INSTANCE.inet_addr(EOsocketTest.LOCALHOST)
+            Integer.reverseBytes(Winsock.INSTANCE.inet_addr(EOsocketTest.LOCALHOST))
         );
         final int connected = Winsock.INSTANCE.connect(socket, addr, addr.size());
         final int error;