diff --git a/ChangeLog b/ChangeLog
index e59120082..13ba69e65 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -33,6 +33,7 @@ Changes
    * Provide an empty implementation of mbedtls_pkcs5_pbes2() when
      MBEDTLS_ASN1_PARSE_C is not enabled. This allows the use of PBKDF2
      without PBES2. Fixed by Marcos Del Sol Vives.
+   * Improve the documentation of mbedtls_net_accept(). Contributed by Ivan Krylov.
 
 = mbed TLS 2.1.11 branch released 2018-03-16
 
diff --git a/include/mbedtls/net.h b/include/mbedtls/net.h
index 8c6534cfb..1b59d18c0 100644
--- a/include/mbedtls/net.h
+++ b/include/mbedtls/net.h
@@ -117,9 +117,10 @@ int mbedtls_net_bind( mbedtls_net_context *ctx, const char *bind_ip, const char
  *
  * \param bind_ctx  Relevant socket
  * \param client_ctx Will contain the connected client socket
- * \param client_ip Will contain the client IP address
+ * \param client_ip Will contain the client IP address, can be NULL
  * \param buf_size  Size of the client_ip buffer
- * \param ip_len    Will receive the size of the client IP written
+ * \param ip_len    Will receive the size of the client IP written,
+ *                  can be NULL if client_ip is null
  *
  * \return          0 if successful, or
  *                  MBEDTLS_ERR_NET_ACCEPT_FAILED, or