ftp: Add docker network create

docs/services/ftp.md

@@ -14,6 +14,19 @@ Theme: [h5ai](https://larsjung.de/h5ai/)
 
 Deploy: [ftp.sh](https://github.com/ustclug/docker-run-script/blob/master/ftp/ftp.sh)
 
+Docker network (in case of need):
+
+```shell
+docker network create \
+  -d macvlan \
+  -o parent=ustclug-master \
+  --subnet=10.254.1.0/24 \
+  ustclug
+```
+
+Note that the name `ustclug-master` is fixed by udev.
+Inspect `/etc/udev/rules.d/*.rules` for details.
+
 ## Notes
 
 1.  SSL cert is required when running LUG FTP.
@@ -22,5 +35,4 @@ Deploy: [ftp.sh](https://github.com/ustclug/docker-run-script/blob/master/ftp/ft
     1. It is strongly suggested to keep permission & owner metadata when backing up/restoring.
     2. Public folder root: set owner `root:root` and permission 0755.
     3. Subfolders: set owner to `1000:1000`. `_h5ai` and `wp-content` needs to be set to a different owner (misconfigured?). And `Incoming` shall be set to 0775.
-4.  Do not use Google DNS in host, as China Mobile network may drop UDP packets to 8.8.8.8. A misconfigured DNS may lead to LDAP in container broken.
-5.  Port 22 is delegated to the LUG FTP container for SFTP, and SSH access to the host has been reassigned to port 2222.
+4.  Port 22 is delegated to the LUG FTP container for SFTP, and SSH access to the host has been reassigned to port 2222.