diff --git a/src/csocket.c b/src/csocket.c
index f4bcfec..ef48c09 100644
--- a/src/csocket.c
+++ b/src/csocket.c
@@ -111,7 +111,7 @@ f2b_conn_process(f2b_conn_t *conn, bool in, void (*cb)(const f2b_cmd_t *cmd, f2b
           cb(cmd, &conn->send); /* handle command */
           f2b_cmd_destroy(cmd);
         } else {
-          f2b_buf_append(&conn->send, "can't parse input, try 'help'\n", 0);
+          f2b_buf_append(&conn->send, "-can't parse input, try 'help'\n", 0);
         }
         free(line);
       }
diff --git a/src/daemon.c b/src/daemon.c
index 5031e92..b75a309 100644
--- a/src/daemon.c
+++ b/src/daemon.c
@@ -103,7 +103,7 @@ f2b_csocket_cmd_process(const f2b_cmd_t *cmd, f2b_buf_t *res) {
 
   if (cmd->type >= CMD_JAIL_STATUS && cmd->type <= CMD_JAIL_FILTER_RELOAD) {
     if ((jail = f2b_jail_find(jails, cmd->args[1])) == NULL) {
-      len = snprintf(buf, sizeof(buf), "can't find jail '%s'\n", cmd->args[1]);
+      len = snprintf(buf, sizeof(buf), "-can't find jail '%s'\n", cmd->args[1]);
       f2b_buf_append(res, buf, len);
       return;
     }
@@ -154,21 +154,21 @@ f2b_csocket_cmd_process(const f2b_cmd_t *cmd, f2b_buf_t *res) {
       f2b_filter_cmd_stats(buf, sizeof(buf), jail->filter);
       f2b_buf_append(res, buf, 0);
     } else {
-      f2b_buf_append(res, "this jail has no filter\n", 0);
+      f2b_buf_append(res, "-this jail has no filter\n", 0);
     }
   } else if (cmd->type == CMD_JAIL_FILTER_RELOAD) {
     if (jail->flags & JAIL_HAS_FILTER) {
       f2b_filter_cmd_reload(buf, sizeof(buf), jail->filter);
       f2b_buf_append(res, buf, 0);
     } else {
-      f2b_buf_append(res, "this jail has no filter\n", 0);
+      f2b_buf_append(res, "-this jail has no filter\n", 0);
     }
   } else {
-    f2b_buf_append(res, "error: unknown command\n", 0);
+    f2b_buf_append(res, "-error: unknown command\n", 0);
   }
 
   if (res->used == 0)
-    f2b_buf_append(res, "ok\n", 3); /* default reply if not set above */
+    f2b_buf_append(res, "+ok\n", 3); /* default reply if not set above */
 
   return;
 }
diff --git a/src/filter.c b/src/filter.c
index 2023326..210674a 100644
--- a/src/filter.c
+++ b/src/filter.c
@@ -240,8 +240,8 @@ f2b_filter_cmd_reload(char *buf, size_t bufsize, f2b_filter_t *filter) {
 
   filter->flush(filter->cfg);
   if ((c = f2b_filter_load_file(filter, filter->init)) > 0) {
-    snprintf(buf, bufsize, "loaded %zu regexps\n", c);
+    snprintf(buf, bufsize, "+loaded %zu regexps\n", c);
   } else {
-    snprintf(buf, bufsize, "can't reload filter\n");
+    snprintf(buf, bufsize, "-can't reload filter\n");
   }
 }
diff --git a/src/jail.c b/src/jail.c
index f6e89c2..6347dd1 100644
--- a/src/jail.c
+++ b/src/jail.c
@@ -586,7 +586,7 @@ f2b_jail_cmd_set(char *res, size_t ressize, f2b_jail_t *jail, const char *param,
 
   if (f2b_jail_set_param(jail, param, value))
     return;
-  snprintf(res, ressize, "parameter not found: %s", param);
+  snprintf(res, ressize, "-parameter not found: %s", param);
 }
 
 /**
@@ -612,7 +612,7 @@ f2b_jail_cmd_ip_xxx(char *res, size_t ressize, f2b_jail_t *jail, int op, const c
       /* ban */
       time_t now = time(NULL);
       if ((addr = f2b_ipaddr_create(ip)) == NULL) {
-        snprintf(res, ressize, "can't parse ip address: %s", ip);
+        snprintf(res, ressize, "-can't parse ip address: %s", ip);
         return;
       }
       addr->lastseen = now;
@@ -625,7 +625,7 @@ f2b_jail_cmd_ip_xxx(char *res, size_t ressize, f2b_jail_t *jail, int op, const c
         jail->sfile->need_save = true;
     } else {
       /* unban & status */
-      snprintf(res, ressize, "can't find ip '%s' in jail '%s'\n", ip, jail->name);
+      snprintf(res, ressize, "-can't find ip '%s' in jail '%s'\n", ip, jail->name);
       return;
     }
   }