diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index adb18ab..9d41cb4 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -1233,6 +1233,14 @@
 }
 
 #if defined(MBEDTLS_SSL_SRV_C)
+void mbedtls_ssl_conf_cert_cb( mbedtls_ssl_config *conf,
+                               int (*f_cert_cb)(mbedtls_ssl_context *) )
+{
+    conf->f_cert_cb = f_cert_cb;
+}
+#endif /* MBEDTLS_SSL_SRV_C */
+
+#if defined(MBEDTLS_SSL_SRV_C)
 void mbedtls_ssl_conf_session_cache( mbedtls_ssl_config *conf,
                                      void *p_cache,
                                      mbedtls_ssl_cache_get_t *f_get_cache,