OuSubnetResolver

Resolves the per-customer LAN CIDR used to size DHCP scopes, derive static reservations, and configure the OPNsense LAN side. Default convention: 10.X.0.0/24 where X is 1-based OU index (1..254). When OuSubnets carries an explicit entry, that value wins.

public static class OuSubnetResolver

1. Fields

1.1. DefaultOuIndex

Default base subnet octet when no explicit OU subnet provided (10.X.0.0/24).

public const int DefaultOuIndex

2. Methods

2.1. AutoCidrForIndex(int)

Auto-derived CIDR for an OU index: 10.{index}.0.0/24. Index clamped to 1..254.

public static string AutoCidrForIndex(int index)

Table 1. Parameters
Name	Type	Description
index	int

Returns: string

2.2. DhcpPoolEnd(string, int)

Returns the DHCP-pool end address (default {net}.199) for the CIDR.

public static string DhcpPoolEnd(string cidr, int end = 199)

Table 2. Parameters
Name	Type	Description
cidr	string
end	int

Returns: string

2.3. DhcpPoolStart(string, int)

Returns the DHCP-pool start address (default offset 100 from network base) for the CIDR. Used to seed OPNsense DHCP scope. Caller pairs with DhcpPoolEnd(string, int).

public static string DhcpPoolStart(string cidr, int offset = 100)

Table 3. Parameters
Name	Type	Description
cidr	string
offset	int

Returns: string

2.4. GatewayAddress(string)

Returns the gateway IP of the CIDR (typically {net}.1). For non-/24 prefixes, computes the first host address in the network.

public static string GatewayAddress(string cidr)

Table 4. Parameters
Name	Type	Description
cidr	string

Returns: string

2.5. ParseCidr(string)

Parses a CIDR like 10.1.0.0/24 into network address + prefix length. Throws NETSetupException when the input is malformed.

public static (IPAddress NetworkAddress, int PrefixLength) ParseCidr(string cidr)

Table 5. Parameters
Name	Type	Description
cidr	string

Returns: (IPAddress NetworkAddress, int PrefixLength)

2.6. ResolveForOu(NETSetupConfig, string, int)

Resolves CIDR for a specific OU. If OuSubnets has the key, returns it; else returns the auto-computed 10.{ouIndex}.0.0/24. ouIndex must be in 1..254 (octet range).

public static string ResolveForOu(NETSetupConfig config, string ouName, int ouIndex)

Table 6. Parameters
Name	Type	Description
config	NETSetupConfig
ouName	string
ouIndex	int

Returns: string

2.7. ResolveLanCidr(NETSetupConfig)

Returns the primary LAN CIDR. Picks the first entry from OuSubnets when present; otherwise falls back to 10.1.0.0/24.

public static string ResolveLanCidr(NETSetupConfig config)

Table 7. Parameters
Name	Type	Description
config	NETSetupConfig

Returns: string