# Network Subnets

> The IP ranges behind every network the wizard creates, and when to leave them alone.

Source: https://joinnasnet.com/en/guides/nasnet-connect/lan/subnets/
Last updated: 2026-08-14

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## Overview

**Network Subnets**, described as *"Configure IP subnets for your network
segments with smart validation and conflict detection"*, is the last sub-step of **LAN** and
appears only in **Advanced Mode**. Everything you configured earlier (base
networks, WAN links, VPN servers, VPN clients, tunnels) needs an address range,
and this is where those ranges are set.

The screen opens with the subnet editor switched off, showing the defaults that
will be used. The app's own advice is to leave them that way unless you have a
reason not to: *"Warning: Only modify these settings if you have technical
networking knowledge. Incorrect subnet values may cause network connectivity
issues and routing problems."*

Subnets are grouped into tabs, and each tab is populated from what you actually
configured. If you did not add any tunnels, the Tunnel tab is empty.

## Before you start

- The defaults follow a deliberate scheme that the app calls *"a systematic
  subnet configuration that helps organize and manage your network
  effectively"*. Changing one range means checking it does not collide with
  another.
- The editor validates as you type and flags overlaps as **Subnet Conflicts
  Detected**. You cannot save with conflicts outstanding.

## Steps

1. Review the defaults under **Using Default Network Configuration**.
2. If you need to change them, switch on **Enable Subnets**.
3. Work through the tabs and edit the third octet of each range.
4. Fix any conflicts flagged in red.
5. Click **Save & Continue** when the screen reports **Configuration valid**.

## Reference

Tabs:

| Tab | What it covers |
| --- | -------------- |
| **Base** | Core network segments for your router configuration |
| **Domestic** | Multiple domestic WAN link subnets for routing segregation |
| **Foreign** | Multiple foreign WAN link subnets for international routing |
| **VPN Server** | Dedicated subnets for VPN client connections |
| **VPN Client** | Dedicated subnets for multiple VPN client connections |
| **Tunnel** | Point-to-point tunnel connections with `/30` subnets |

Base networks and their purpose:

| Network | Purpose |
| ------- | ------- |
| **Split Network** | Mixed domestic and foreign traffic |
| **Domestic Network** | Domestic-only traffic |
| **Foreign Network** | Foreign/international traffic |
| **VPN Network** | VPN client traffic |

Defaults applied when you do not change them:

| Network | Default range |
| ------- | ------------- |
| Split | `192.168.10.0/24` |
| Domestic | `192.168.20.0/24` |
| Foreign | `192.168.30.0/24` |
| VPN | `192.168.40.0/24` |
| Domestic WAN links | `192.168.21.0/24` onwards, one per link |
| Foreign WAN links | `192.168.31.0/24` onwards, one per link |
| VPN client networks | `192.168.41.0/24` onwards, one per client |
| WireGuard servers | `192.168.110.0/24` onwards |
| OpenVPN servers | `192.168.120.0/24` onwards |
| PPTP server | `192.168.130.0/24` |
| SSTP server | `192.168.140.0/24` |
| L2TP server | `192.168.150.0/24` |
| IKEv2 server | `192.168.160.0/24` |

Validation rules:

| Rule | Message |
| ---- | ------- |
| Range | Value must be between 1–254 |
| Reserved | Values 1 and 255 are reserved |
| Required | This subnet is required |
| Conflict | Conflicts with another configured network |

## Troubleshooting

**"Subnet Conflicts Detected".** Two networks were given overlapping ranges. The
banner names which, and lists how many rows in the section are affected. Change
one of them and the warning clears.

## Related

- [LAN Interfaces](/en/guides/nasnet-connect/lan/interfaces/)
- [Network Tunnels](/en/guides/nasnet-connect/lan/tunnel/)
- [Easy mode vs Advanced mode](/en/guides/nasnet-connect/easy-vs-advanced/)