diff --git a/lib/libc/net/gai_strerror.c b/lib/libc/net/gai_strerror.c
index 5611559cfe0c..4f60f2db3917 100644
--- a/lib/libc/net/gai_strerror.c
+++ b/lib/libc/net/gai_strerror.c
@@ -30,7 +30,17 @@
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
+#include "namespace.h"
 #include <netdb.h>
+#if defined(NLS)
+#include <nl_types.h>
+#include <errno.h>
+#include <limits.h>
+#include <stdlib.h>
+#include <string.h>
+#include "reentrant.h"
+#endif
+#include "un-namespace.h"
 
 /* Entries EAI_ADDRFAMILY (1) and EAI_NODATA (7) are obsoleted, but left */
 /* for backward compatibility with userland code prior to 2553bis-02 */
@@ -52,9 +62,57 @@ static const char *ai_errlist[] = {
 	"Argument buffer overflow"			/* EAI_OVERFLOW */
 };
 
+#if defined(NLS)
+static char		gai_buf[NL_TEXTMAX];
+static once_t		gai_init_once = ONCE_INITIALIZER;
+static thread_key_t	gai_key;
+static int		gai_keycreated = 0;
+
+static void
+gai_keycreate(void)
+{
+	gai_keycreated = (thr_keycreate(&gai_key, free) == 0);
+}
+#endif
+
 const char *
 gai_strerror(int ecode)
 {
+#if defined(NLS)
+	nl_catd catd;
+	char *buf;
+
+	if (thr_main() != 0)
+		buf = gai_buf;
+	else {
+		if (thr_once(&gai_init_once, gai_keycreate) != 0 ||
+		    !gai_keycreated)
+			goto thr_err;
+		if ((buf = thr_getspecific(gai_key)) == NULL) {
+			if ((buf = malloc(sizeof(gai_buf))) == NULL)
+				goto thr_err;
+			if (thr_setspecific(gai_key, buf) != 0) {
+				free(buf);
+				goto thr_err;
+			}
+		}
+	}
+
+	catd = catopen("libc", NL_CAT_LOCALE);
+	if (ecode > 0 && ecode < EAI_MAX)
+		strlcpy(buf, catgets(catd, 3, ecode, ai_errlist[ecode]),
+		    sizeof(gai_buf));
+	else if (ecode == 0)
+		strlcpy(buf, catgets(catd, 3, NL_MSGMAX - 1, "Success"),
+		    sizeof(gai_buf));
+	else
+		strlcpy(buf, catgets(catd, 3, NL_MSGMAX, "Unknown error"),
+		    sizeof(gai_buf));
+	catclose(catd);
+	return buf;
+
+thr_err:
+#endif
 	if (ecode >= 0 && ecode < EAI_MAX)
 		return ai_errlist[ecode];
 	return "Unknown error";
diff --git a/lib/libc/nls/C.msg b/lib/libc/nls/C.msg
index b25e83f330ab..2210df6cc463 100644
--- a/lib/libc/nls/C.msg
+++ b/lib/libc/nls/C.msg
@@ -257,3 +257,39 @@ $ SIGUSR1
 30 User defined signal 1
 $ SIGUSR2
 31 User defined signal 2
+$
+$ gai_strerror() support catalog
+$
+$set 3
+$ 1 (obsolete)
+1 Address family for hostname not supported
+$ EAI_AGAIN
+2 Temporary failure in name resolution
+$ EAI_BADFLAGS
+3 Invalid value for ai_flags
+$ EAI_FAIL
+4 Non-recoverable failure in name resolution
+$ EAI_FAMILY
+5 ai_family not supported
+$ EAI_MEMORY
+6 Memory allocation failure
+$ 7 (obsolete)
+7 No address associated with hostname
+$ EAI_NONAME
+8 hostname nor servname provided, or not known
+$ EAI_SERVICE
+9 servname not supported for ai_socktype
+$ EAI_SOCKTYPE
+10 ai_socktype not supported
+$ EAI_SYSTEM
+11 System error returned in errno
+$ EAI_BADHINTS
+12 Invalid value for hints
+$ EAI_PROTOCOL
+13 Resolved protocol is unknown
+$ EAI_OVERFLOW
+14 Argument buffer overflow
+$ 0
+32766 Success
+$ NL_MSGMAX
+32767 Unknown error