diff --git a/src/algo_naive.c b/src/algo_naive.c
index 6853244..a32137f 100644
--- a/src/algo_naive.c
+++ b/src/algo_naive.c
@@ -22,7 +22,7 @@ void on_tcp_co(struct evt_core_ctx* ctx, struct evt_core_cat* cat, int fd) {
   conn_sock = accept(fd, &in_addr, &in_len);
   if (conn_sock == -1) goto co_error;
   evt_core_add_fd (ctx, "tcp-read", fd);
-  evt_core_add_fd (ctx, "tcp-write", fd);
+  evt_core_add_fd (ctx, "tcp-write", dup(fd));
 
   return;
 
diff --git a/src/donar_server.c b/src/donar_server.c
index ee8cf82..bf377db 100644
--- a/src/donar_server.c
+++ b/src/donar_server.c
@@ -49,9 +49,15 @@ void donar_server(struct donar_server_ctx* ctx, struct algo_skel* algo, char* ud
   evt_core_add_cat (&(ctx->evts), &(algo->on_udp_write));
   evt_core_add_cat (&(ctx->evts), &(algo->on_tcp_write));
 
+  printf("--- Categories created\n");
   int sock = create_udp_client (udp_host, udp_port);
+  if (sock < 0) {
+    fprintf(stderr, "Unable to create a UDP client socket\n");
+    exit(EXIT_FAILURE);
+  }
   evt_core_add_fd (&(ctx->evts), "udp-read", sock);
-  evt_core_add_fd (&(ctx->evts), "udp-write", sock);
+  evt_core_add_fd (&(ctx->evts), "udp-write", dup(sock));
+  printf("--- UDP client is connected\n");
 
   for (uint16_t i = 0; i < PORT_SIZE ; i++) {
     ctx->ports[i] = 7500 + i;
@@ -59,6 +65,7 @@ void donar_server(struct donar_server_ctx* ctx, struct algo_skel* algo, char* ud
   create_onion_services (&(ctx->tos), &(ctx->tctl), ctx->ports, PORT_SIZE);
   printf("--- Onion services created\n");
   init_tcp_servers(ctx);
+  printf("--- TCP servers are listening\n");
 
   evt_core_loop (&(ctx->evts));
 
diff --git a/src/evt_core.c b/src/evt_core.c
index eb221c0..1e27d8b 100644
--- a/src/evt_core.c
+++ b/src/evt_core.c
@@ -34,7 +34,6 @@ void evt_core_add_cat(struct evt_core_ctx* ctx, struct evt_core_cat* cat) {
     fprintf(stderr, "cat->socklist must be null. What have you done?\n");
     exit(EXIT_FAILURE);
   }
-  cat->socklist = g_array_new (FALSE, FALSE, sizeof(int));
 
   struct evt_core_cat* dyn = NULL;
   dyn = malloc(sizeof(struct evt_core_cat));
@@ -47,6 +46,7 @@ void evt_core_add_cat(struct evt_core_ctx* ctx, struct evt_core_cat* cat) {
   dyn->cb = cat->cb;
   dyn->name = strdup(cat->name);
   dyn->flags = cat->flags;
+  dyn->socklist = g_array_new (FALSE, FALSE, sizeof(int));
 
   if (dyn->name == NULL) {
     perror("Unable to allocate memory for category name via strdup");
@@ -71,7 +71,7 @@ void evt_core_add_fd(struct evt_core_ctx* ctx, char* name, int fd) {
     perror("Unable to allocate memory for key via malloc");
     exit(EXIT_FAILURE);
   }
-  memcpy(key, &fd, sizeof(int));
+  *key = fd;
 
   struct evt_core_cat* cat = g_hash_table_lookup(ctx->catlist, name);
   if (cat == NULL) {
@@ -80,7 +80,7 @@ void evt_core_add_fd(struct evt_core_ctx* ctx, char* name, int fd) {
   }
 
   g_array_append_val (cat->socklist, fd);
-  g_hash_table_insert(ctx->socklist, key, cat);
+  g_hash_table_insert(ctx->socklist, key, cat); // broken
   add_fd_to_epoll(ctx->epollfd, fd, cat->flags);
 }
 
@@ -103,10 +103,11 @@ void evt_core_loop(struct evt_core_ctx* ctx) {
     }
 
     for (n = 0 ; n < num_fd; n++) {
-       if ((events[n].events & EPOLLERR) || (events[n].events & EPOLLHUP) || (!(events[n].events & EPOLLIN))) {
+      if ((events[n].events & EPOLLERR) || (events[n].events & EPOLLHUP) || (!(events[n].events & EPOLLIN))) {
         /* An error has occured on this fd, or the socket is not
            ready for reading (why were we notified then?) */
-	      fprintf (stderr, "epoll error\n");
+
+	      fprintf (stderr, "An epoll error occured with fd=%d\n", events[n].data.fd);
 	      close (events[n].data.fd);
 	      continue;
 	    }
diff --git a/src/net_tools.c b/src/net_tools.c
index e2c3371..78dbdd5 100644
--- a/src/net_tools.c
+++ b/src/net_tools.c
@@ -128,10 +128,14 @@ void fill_buffer(size_t* written, char* dest, void *src, size_t n) {
  * You need to read everything before going back to epoll
  * Which means keeping state too
  */
-void add_fd_to_epoll(int epollfd, int fd, int flags) {
-  make_socket_non_blocking (fd);
+void add_fd_to_epoll(int epollfd, int fd, uint32_t flags) {
+  int err = make_socket_non_blocking (fd);
+  if (err == -1) {
+    fprintf(stderr, "Unable to set fd=%d to non blocking\n", fd);
+    exit(EXIT_FAILURE);
+  }
 
-  struct epoll_event current_event;
+  struct epoll_event current_event = {0};
   //current_event.events = EPOLLIN | EPOLLET;
   current_event.events = flags;
   current_event.data.fd = fd;
diff --git a/src/net_tools.h b/src/net_tools.h
index 4bcd539..1ec2be8 100644
--- a/src/net_tools.h
+++ b/src/net_tools.h
@@ -12,6 +12,6 @@ int create_tcp_client(char* host, char* service);
 int create_udp_client(char* host, char* service);
 int create_tcp_server(char* service);
 int make_socket_non_blocking(int fd);
-void add_fd_to_epoll(int epollfd, int fd, int flags);
+void add_fd_to_epoll(int epollfd, int fd, uint32_t flags);
 int read_entity(int fd, void* entity, int size);
 void fill_buffer(size_t* written, char* dest, void *src, size_t n);