Change topology net30 to topology subnet
By default, the OpenVPN server sends to the client the option **topology net30**
```
Nov 6 15:58:45 omnia1 openvpn(turris)[8508]: PUSH: Received control message: 'PUSH_REPLY,route 198.18.2.0 255.255.255.0,route 48.0.0.0 255.255.0.0,route 10.111.111.1,topology net30,ping 10,ping-restart 120,ifconfig 10.111.111.6 10.111.111.5,peer-id 0,cipher AES-256-GCM'
```
This option is deprecated and for legacy clients only (year 2014). By configuring the **topology subnet** directive, it makes the routing table easier to read and simplifies the routing.
```
uci set openvpn.server_turris.topology='subnet'
```
```
Nov 6 16:10:42 omnia1 openvpn(turris)[11847]: PUSH: Received control message: 'PUSH_REPLY,route 198.18.2.0 255.255.255.0,route 48.0.0.0 255.255.0.0,route-gateway 10.111.111.1,topology subnet,ping 10,ping-restart 120,ifconfig 10.111.111.4 255.255.255.0,peer-id 0,cipher AES-256-GCM'
```
[OpenVPN Topology](https://community.openvpn.net/openvpn/wiki/Topology)
issue