# isMainnetHost

> **isMainnetHost**(`host?`): `boolean`

Defined in: [utils/helper.ts:177](https://github.com/B3Pay/ic-reactor/blob/2de45f357e6c8bcfa7cb2aa71eff7a059eacdf01/packages/core/src/utils/helper.ts#L177)

Checks if a given host URL is a mainnet Internet Computer boundary node host.

Note this recognises only the canonical boundary domains: a mainnet dapp on a
custom domain returns `false`. Do not use it as a "safe to trust local
configuration" test — see [allowsEnvRootKey](allowsEnvRootKey.md).

## Parameters

### host?

`string`

The host URL to evaluate.

## Returns

`boolean`

`true` if the host is a mainnet host, default to true if host is undefined, otherwise `false`.