Tracked clicks, opens, the online version, and unsubscribe links need a host that is not your From domain. A **custom click domain** is the durable fix: recipients see your brand, and a blocklist hit on Lumail's shared fallback cannot take your mail down.

## Why this matters

The shared fallback lives under a dedicated `lt.` zone, one hostname per organization (`<org-id>.lt.<shared-domain>`). That isolates host-level filters and tells us which org caused a spike. Slugs can be renamed and reused, so minted hosts use the stable org id. It does **not** protect against a Spamhaus DBL listing of the shared registrable domain — DBL lists the registrable domain, so every subdomain follows.

Your own verified web domain used as a click domain keeps reputation aligned with the domain you already send from.

## Set one up

1. Add and verify a [web domain](/docs/domains/web-domains) (`click.yourdomain.com` is the usual name).
2. Open **Settings → Click domain**.
3. Select that verified domain.

New tracked links then mint on `https://click.yourdomain.com/...` with no extra subdomain. Already-sent mail on the shared host keeps working.

## Shared fallback

Organizations without a custom click domain mint on Lumail's current shared zone. Prefer setting your own domain before a large send, especially on a young or newly recovered shared host.