diff --git a/msvc/ecl/config.h.msvc6 b/msvc/ecl/config.h.msvc6
index bd77eb10..b0a7490e 100755
--- a/msvc/ecl/config.h.msvc6
+++ b/msvc/ecl/config.h.msvc6
@@ -76,8 +76,8 @@
 #define ECL_LIBATOMIC_OPS_H
 
 /* Network streams							*/
-#define TCP 1
-#if defined(TCP) && (defined(_MSC_VER) || defined(mingw32))
+#define ECL_TCP 1
+#if defined(ECL_TCP) && (defined(_MSC_VER) || defined(mingw32))
 # define ECL_WSOCK
 #endif
 
diff --git a/src/c/main.d b/src/c/main.d
index e5343edc..9e02d687 100755
--- a/src/c/main.d
+++ b/src/c/main.d
@@ -296,7 +296,7 @@ cl_shutdown(void)
 #ifdef ENABLE_DLOPEN
     ecl_library_close_all();
 #endif
-#ifdef TCP
+#ifdef ECL_TCP
     ecl_tcp_close_all();
 #endif
   }
diff --git a/src/c/symbols_list.h b/src/c/symbols_list.h
index 230941c2..84bfeae1 100755
--- a/src/c/symbols_list.h
+++ b/src/c/symbols_list.h
@@ -45,7 +45,7 @@ typedef struct {
 #else
 # define IF_MP(x) NULL
 #endif
-#ifdef TCP
+#ifdef ECL_TCP
 # define IF_TCP(x) x
 #else
 # define IF_TCP(x) NULL
@@ -1323,13 +1323,13 @@ cl_symbols[] = {
 {SYS_ "DISPLAY-PROFILE", SI_ORDINARY, IF_PROFILE(si_display_profile), -1, OBJNULL},
 /* #endif PROFILE */
 
-/* #ifdef TCP */
+/* #ifdef ECL_TCP */
 {SYS_ "*PROFILE-ARRAY*", SI_SPECIAL, NULL, -1, OBJNULL},
 {SYS_ "OPEN-CLIENT-STREAM", SI_ORDINARY, IF_TCP(si_open_client_stream), 2, OBJNULL},
 {SYS_ "OPEN-SERVER-STREAM", SI_ORDINARY, IF_TCP(si_open_server_stream), 1, OBJNULL},
 {SYS_ "OPEN-UNIX-SOCKET-STREAM", SI_ORDINARY, IF_TCP(si_open_unix_socket_stream), 1, OBJNULL},
 {SYS_ "LOOKUP-HOST-ENTRY", SI_ORDINARY, IF_TCP(si_lookup_host_entry), 1, OBJNULL},
-/* #endif TCP */
+/* #endif ECL_TCP */
 
 {EXT_ "CATCH-SIGNAL", EXT_ORDINARY, si_catch_signal, -3, OBJNULL},
 {EXT_ "GET-SIGNAL-HANDLER", EXT_ORDINARY, si_get_signal_handler, 1, OBJNULL},
diff --git a/src/c/symbols_list2.h b/src/c/symbols_list2.h
index d7fab9b2..4439fcbe 100644
--- a/src/c/symbols_list2.h
+++ b/src/c/symbols_list2.h
@@ -45,7 +45,7 @@ typedef struct {
 #else
 # define IF_MP(x) NULL
 #endif
-#ifdef TCP
+#ifdef ECL_TCP
 # define IF_TCP(x) x
 #else
 # define IF_TCP(x) NULL
@@ -1323,13 +1323,13 @@ cl_symbols[] = {
 {SYS_ "DISPLAY-PROFILE",IF_PROFILE("si_display_profile"),-1},
 /* #endif PROFILE */
 
-/* #ifdef TCP */
+/* #ifdef ECL_TCP */
 {SYS_ "*PROFILE-ARRAY*",NULL,-1},
 {SYS_ "OPEN-CLIENT-STREAM",IF_TCP("si_open_client_stream"),2},
 {SYS_ "OPEN-SERVER-STREAM",IF_TCP("si_open_server_stream"),1},
 {SYS_ "OPEN-UNIX-SOCKET-STREAM",IF_TCP("si_open_unix_socket_stream"),1},
 {SYS_ "LOOKUP-HOST-ENTRY",IF_TCP("si_lookup_host_entry"),1},
-/* #endif TCP */
+/* #endif ECL_TCP */
 
 {EXT_ "CATCH-SIGNAL","si_catch_signal",-3},
 {EXT_ "GET-SIGNAL-HANDLER","si_get_signal_handler",1},
diff --git a/src/configure b/src/configure
index ed5c52c4..8cad6587 100755
--- a/src/configure
+++ b/src/configure
@@ -9951,7 +9951,7 @@ LSP_FEATURES="(cons :builtin-sockets ${LSP_FEATURES})"
 fi
 if test "${with_tcp}" = "yes"; then
 
-$as_echo "#define TCP 1" >>confdefs.h
+$as_echo "#define ECL_TCP 1" >>confdefs.h
 
   EXTRA_OBJS="${EXTRA_OBJS} tcp.${OBJEXT}"
 
diff --git a/src/configure.ac b/src/configure.ac
index 286faa87..22bd93dc 100644
--- a/src/configure.ac
+++ b/src/configure.ac
@@ -833,7 +833,7 @@ if test "${with_tcp}" = "builtin"; then
   with_tcp=yes
 fi
 if test "${with_tcp}" = "yes"; then
-  AC_DEFINE(TCP, [1], [Network streams])
+  AC_DEFINE(ECL_TCP, [1], [Network streams])
   EXTRA_OBJS="${EXTRA_OBJS} tcp.${OBJEXT}"
   ECL_ADD_LISP_MODULE([sockets])
   LIBS="${LIBS} ${TCPLIBS}"
diff --git a/src/ecl/configpre.h b/src/ecl/configpre.h
index aeda058e..436e17aa 100644
--- a/src/ecl/configpre.h
+++ b/src/ecl/configpre.h
@@ -637,7 +637,7 @@
 #undef STDC_HEADERS
 
 /* Network streams */
-#undef TCP
+#undef ECL_TCP
 
 /* Define to 1 if you can safely include both <sys/time.h> and <time.h>. */
 #undef TIME_WITH_SYS_TIME
diff --git a/src/h/config.h.in b/src/h/config.h.in
index 7a68a3a4..1550bdcd 100644
--- a/src/h/config.h.in
+++ b/src/h/config.h.in
@@ -88,8 +88,8 @@
 #undef ECL_LIBATOMIC_OPS_H
 
 /* Network streams                                                      */
-#undef TCP
-#if defined(TCP) && defined(ECL_MS_WINDOWS_HOST)
+#undef ECL_TCP
+#if defined(ECL_TCP) && defined(ECL_MS_WINDOWS_HOST)
 # define ECL_WSOCK
 #endif
 
diff --git a/src/h/external.h b/src/h/external.h
index f4d3004c..9572f14c 100755
--- a/src/h/external.h
+++ b/src/h/external.h
@@ -1753,7 +1753,7 @@ extern ECL_API cl_object mp_compare_and_swap_symbol_plist(cl_object x, cl_object
 
 /* tcp.c */
 
-#ifdef TCP
+#ifdef ECL_TCP
 extern ECL_API cl_object si_open_client_stream(cl_object host, cl_object port);
 extern ECL_API cl_object si_open_server_stream(cl_object port);
 extern ECL_API cl_object si_open_unix_socket_stream(cl_object path);