@@ -299,6 +299,11 @@ modparam("http_async_client", "tls_ca_path", "/etc/kamailio/ssl/ca/")

         <para>

 		    If defined to a non-zero value, TCP keepalive will be enabled on cURL connections.

 		</para>

+        <para>

+            <emphasis>

+            Requires libcurl >= 7.25.0

+            </emphasis>

+		</para>

 		<para>

 		<emphasis>

 			Default value is 0 (disabled).

@@ -529,6 +529,7 @@ int new_request(str *query, http_m_params_t *query_params, http_multi_cbe_t cb,

     /* enable tcp keepalives for the handler */

 	if (cell->params.tcp_keepalive) {

+#ifdef CURLOPT_TCP_KEEPALIVE

 		LM_DBG("Enabling TCP keepalives\n");

 		curl_easy_setopt(cell->easy, CURLOPT_TCP_KEEPALIVE, 1L);

@@ -541,6 +542,9 @@ int new_request(str *query, http_m_params_t *query_params, http_multi_cbe_t cb,

 			curl_easy_setopt(cell->easy, CURLOPT_TCP_KEEPINTVL, cell->params.tcp_ka_interval);

 			LM_DBG("CURLOPT_TCP_KEEPINTERVAL set to %d\n", cell->params.tcp_ka_interval);

 		}

+#else

+		LM_DBG("tcp_keepalive configured, but installed cURL version doesn't include CURLOPT_TCP_KEEPINTERVAL.\n");

+#endif

 	}

     LM_DBG("Adding easy %p to multi %p (%.*s)\n", cell->easy, g->multi, query->len, query->s);