# Settings

Multicast DNS, or mDNS, lets devices on the local network discover services without a conventional DNS server. Sylve advertises its mDNS records only while the **mDNS** system service is enabled. Enable it from **System Settings → Services** before configuring this page.

The settings are shared by every user-created mDNS record and by records managed for Samba. They control where Sylve advertises, not which services it advertises. Add those on [Records](/guides/node/network/mdns/records/).

<img
  src={overview.src}
  alt="mDNS Settings table showing igb0 and igb1 as selected interfaces and zeus as the configured hostname"
/>

## Update mDNS settings

Choose **Update** to change the responder configuration. Sylve validates the selection, rebuilds the responder, then saves the change. If the new responder cannot start, the previous active configuration is restored.

<img
  src={update.src}
  alt="Update mDNS Settings dialog with igb0 and igb1 selected and zeus entered as the hostname"
/>

| Field | What it controls |
| --- | --- |
| **Interfaces** | Limits advertisements to the selected network interfaces. Leave it empty to advertise through all available interfaces. A selected interface must still exist when the settings are saved. |
| **Hostname** | The hostname used by the responder. Leave it empty to use the node's system hostname. A custom hostname may contain DNS labels, numbers, and hyphens, with a maximum length of 253 characters. |

## Choosing interfaces

Use a specific LAN-facing interface when mDNS must stay within one network. Leaving the setting empty is useful on a small single-LAN node, but can expose service discovery on every connected network. Interface-specific records can further narrow an individual advertisement; see [Records](/guides/node/network/mdns/records/).

:::note
Changing the system hostname affects mDNS only when **Hostname** is empty here. A hostname set on this page takes precedence.
:::