diff --git a/include/output_rtltcp.h b/include/output_rtltcp.h
index 59ac76e2..58adc879 100644
--- a/include/output_rtltcp.h
+++ b/include/output_rtltcp.h
@@ -26,6 +26,6 @@ struct r_cfg;
     @return The initialized rtltcp output instance.
             You must release this object with raw_output_free once you're done with it.
 */
-struct raw_output *raw_output_rtltcp_create(char const *host, char const *port, struct r_cfg *cfg);
+struct raw_output *raw_output_rtltcp_create(char const *host, char const *port, char const *opts, struct r_cfg *cfg);
 
 #endif /* INCLUDE_OUTPUT_RTLTCP_H_ */
diff --git a/src/output_rtltcp.c b/src/output_rtltcp.c
index ea445514..67598ad2 100644
--- a/src/output_rtltcp.c
+++ b/src/output_rtltcp.c
@@ -98,6 +98,7 @@ typedef struct rtltcp_server {
     socklen_t addr_len;
     SOCKET sock;
     int client_count; ///< number of connected clients
+    int control;      ///< are clients allowed to change SDR parameters
 
     uint8_t const *data_buf; ///< data buffer with most recent data, NULL otherwise
     uint32_t data_len;       ///< data buffer length in bytes, 0 otherwise
@@ -157,7 +158,7 @@ E.g. initialization from Gqrx:
 - RTLTCP_SET_FREQ  with 433968000
 */
 
-static int parse_command(r_cfg_t *cfg, uint8_t const *buf, int len)
+static int parse_command(r_cfg_t *cfg, int control, uint8_t const *buf, int len)
 {
     UNUSED(cfg);
 
@@ -171,21 +172,28 @@ static int parse_command(r_cfg_t *cfg, uint8_t const *buf, int len)
     switch (cmd) {
     case RTLTCP_SET_FREQ:
         print_logf(LOG_DEBUG, "rtl_tcp", "received command SET_FREQ with %u", arg);
-        // set_center_freq(cfg, arg);
+        if (control)
+            set_center_freq(cfg, arg);
         break;
     case RTLTCP_SET_SAMPLE_RATE:
         print_logf(LOG_DEBUG, "rtl_tcp", "received command SET_SAMPLE_RATE with %u", arg);
-        // set_sample_rate(cfg, arg);
+        if (control)
+            set_sample_rate(cfg, arg);
         break;
     case RTLTCP_SET_GAIN_MODE:
         print_logf(LOG_DEBUG, "rtl_tcp", "received command SET_GAIN_MODE with %u", arg);
+        // if (control)
+        // if (arg == 0 /* =auto */) sdr_set_auto_gain(dev, 0);
         break;
     case RTLTCP_SET_GAIN:
         print_logf(LOG_DEBUG, "rtl_tcp", "received command SET_GAIN with %u", arg);
+        // if (control)
+        // sdr_set_tuner_gain(dev, char const *gain_str, 0)
         break;
     case RTLTCP_SET_FREQ_CORRECTION:
         print_logf(LOG_DEBUG, "rtl_tcp", "received command SET_FREQ_CORRECTION with %u", arg);
-        // set_freq_correction(cfg, (int)arg);
+        if (control)
+            set_freq_correction(cfg, (int)arg);
         break;
     case RTLTCP_SET_IF_TUNER_GAIN:
         print_logf(LOG_DEBUG, "rtl_tcp", "received command SET_IF_TUNER_GAIN with %u", arg);
@@ -195,6 +203,7 @@ static int parse_command(r_cfg_t *cfg, uint8_t const *buf, int len)
         break;
     case RTLTCP_SET_AGC_MODE:
         print_logf(LOG_DEBUG, "rtl_tcp", "received command SET_AGC_MODE with %u", arg);
+        // ...
         break;
     case RTLTCP_SET_DIRECT_SAMPLING:
         print_logf(LOG_DEBUG, "rtl_tcp", "received command SET_DIRECT_SAMPLING with %u", arg);
@@ -253,6 +262,7 @@ static THREAD_RETURN THREAD_CALL accept_thread(void *arg)
         unsigned addr_len = sizeof(addr);
         int sock = accept(srv->sock, (struct sockaddr *)&addr, &addr_len);
 
+        // TODO: ignore ECONNABORTED (Software caused connection abort)
         if (sock < 0) {
             perror("ERROR on accept");
             continue;
@@ -308,7 +318,7 @@ static THREAD_RETURN THREAD_CALL accept_thread(void *arg)
                 }
                 int pos = 0;
                 while (pos + 5 <= len) {
-                    pos += parse_command(srv->cfg, &buf[pos], (int)len - pos);
+                    pos += parse_command(srv->cfg, srv->control, & buf[pos], (int)len - pos);
                 }
             }
             if (abort) {
@@ -487,7 +497,7 @@ static void raw_output_rtltcp_free(raw_output_t *output)
     free(rtltcp);
 }
 
-struct raw_output *raw_output_rtltcp_create(const char *host, const char *port, r_cfg_t *cfg)
+struct raw_output *raw_output_rtltcp_create(const char *host, const char *port, char const *opts, r_cfg_t *cfg)
 {
     raw_output_rtltcp_t *rtltcp = calloc(1, sizeof(raw_output_rtltcp_t));
     if (!rtltcp) {
@@ -504,6 +514,14 @@ struct raw_output *raw_output_rtltcp_create(const char *host, const char *port,
     }
 #endif
 
+    // If clients allowed to change SDR parameters
+    if (opts && !strcasecmp(opts, "control"))
+        rtltcp->server.control = 1;
+    else if (opts && *opts) {
+        print_logf(LOG_FATAL, __func__, "Invalid \"%s\" option.", opts);
+        exit(1);
+    }
+
     rtltcp->output.output_frame  = raw_output_rtltcp_frame;
     rtltcp->output.output_free   = raw_output_rtltcp_free;
 
diff --git a/src/r_api.c b/src/r_api.c
index d35b4fe6..d0cd659d 100644
--- a/src/r_api.c
+++ b/src/r_api.c
@@ -1143,7 +1143,7 @@ void add_rtltcp_output(r_cfg_t *cfg, char *param)
     }
     print_logf(LOG_CRITICAL, "rtl_tcp server", "Starting rtl_tcp server at %s port %s", host, port);
 
-    list_push(&cfg->raw_handler, raw_output_rtltcp_create(host, port, cfg));
+    list_push(&cfg->raw_handler, raw_output_rtltcp_create(host, port, extra, cfg));
 }
 
 void add_sr_dumper(r_cfg_t *cfg, char const *spec, int overwrite)