fix to docs; add acl example
@@ -31,9 +31,29 @@ transfer [ZONE...] {
`transfer.Transferer`.
* `to` **ADDRESS...** The hosts *transfer* will transfer to. Use `*` to permit transfers to all
- addresses. **ADDRESS** must be denoted in CIDR notation (e.g., 127.0.0.1/32) or just as plain
- addresses. `to` may be specified multiple times.
+ addresses. Zone change notifications are sent to all **ADDRESS** that are an IP address or
+ an IP address and port e.g. `1.2.3.4`, `12:34::56`, `1.2.3.4:5300`, `[12:34::56]:5300`.
+ `to` may be specified multiple times.
+
+You can use the _acl_ plugin to further restrict hosts permitted to receive a zone transfer.
+See example below.
## Examples
-See the specific plugins using this plugin for examples on it's usage.
+Use in conjuction with the _acl_ plugin to restrict access to subnet 10.1.0.0/16.
+
+```
+...
+ acl {
+ allow type AXFR net 10.1.0.0/16
+ allow type IXFR net 10.1.0.0/16
+ block type AXFR net *
+ block type IXFR net *
+ }
+ transfer {
+ to *
+ }
+...
+```
+
+Each plugin that can use _transfer_ includes an example of use in their respective documentation.
\ No newline at end of file
