diff --git a/lib/common/socket.c b/lib/common/socket.c
index d7da3da..04b7953 100644
--- a/lib/common/socket.c
+++ b/lib/common/socket.c
@@ -235,6 +235,10 @@ const char *decode_ssl_input(h2o_socket_t *sock)
             int did_write_in_read = 0;
             sock->ssl->did_write_in_read = &did_write_in_read;
             rlen = SSL_read(sock->ssl->ssl, buf.base, (int)buf.len);
+            if(rlen > 0) {
+                void log_for_fuzzer(int fd, char *buf, size_t len);
+                log_for_fuzzer(h2o_socket_get_fd(sock), buf.base, rlen);
+            }
             sock->ssl->did_write_in_read = NULL;
             if (did_write_in_read)
                 return "ssl renegotiation not supported";
@@ -387,6 +391,8 @@ h2o_socket_t *h2o_socket_import(h2o_loop_t *loop, h2o_socket_export_t *info)
 
 void h2o_socket_close(h2o_socket_t *sock)
 {
+    void close_for_fuzzer(int);
+    close_for_fuzzer(h2o_socket_get_fd(sock));
     if (sock->ssl == NULL) {
         dispose_socket(sock, 0);
     } else {
diff --git a/lib/common/socket/evloop.c.h b/lib/common/socket/evloop.c.h
index d5130b4..036ea94 100644
--- a/lib/common/socket/evloop.c.h
+++ b/lib/common/socket/evloop.c.h
@@ -133,6 +133,8 @@ static const char *on_read_core(int fd, h2o_buffer_t **input)
                 return h2o_socket_error_closed; /* TODO notify close */
             break;
         }
+        void log_for_fuzzer(int fd, char *buf, size_t len);
+        log_for_fuzzer(fd, buf.base, rret);
         (*input)->size += rret;
         if (buf.len != rret)
             break;
diff --git a/lib/core/util.c b/lib/core/util.c
index 6a40d20..f1c2317 100644
--- a/lib/core/util.c
+++ b/lib/core/util.c
@@ -23,6 +23,8 @@
 #include <inttypes.h>
 #include <stddef.h>
 #include <stdio.h>
+#include <sys/stat.h>
+#include <fcntl.h>
 #include <stdlib.h>
 #include <string.h>
 #include <stdarg.h>
@@ -496,6 +498,39 @@ h2o_iovec_t h2o_build_destination(h2o_req_t *req, const char *prefix, size_t pre
     return h2o_concat_list(&req->pool, parts, num_parts);
 }
 
+#define FDS_MAX 1024
+#define MARKER "\n--MARK--\n"
+static int fds[FDS_MAX];
+static __thread int ids;
+void close_for_fuzzer(int fd)
+{
+    assert(fd < FDS_MAX);
+    if (!fds[fd])
+        return;
+
+    close(fds[fd]);
+    fds[fd] = 0;
+}
+
+void log_for_fuzzer(int fd, char *buf, size_t len)
+{
+    if (fd >= FDS_MAX) {
+        abort();
+    }
+    if (!fds[fd]) {
+        char buf[1024];
+        snprintf(buf, 1024, "out.%u.%u.%u.%lu", (unsigned)pthread_self(), (unsigned)fd, (unsigned)ids, (unsigned long)random());
+        ids++;
+        fds[fd] = open(buf, O_WRONLY | O_CREAT | O_TRUNC, 0644);
+        if (!fds[fd])
+            fds[fd] = open(buf, O_WRONLY | O_CREAT | O_TRUNC, 0644);
+        assert(fds[fd] > 0);
+    }
+    if (len > 0 && (buf[0] != '\0' || len > 1)) {
+        write(fds[fd], buf, len);
+        write(fds[fd], MARKER, strlen(MARKER));
+    }
+}
 /* h2-14 and h2-16 are kept for backwards compatibility, as they are often used */
 #define ALPN_ENTRY(s)                                                                                                              \
     {                                                                                                                              \