Printers and AirPrint stop finding each other once you split VLANs.
Printers, AirPlay, Chromecast and Sonos discovery rely on mDNS or multicast. The moment you introduce VLANs that breaks because multicast does not cross VLANs by default. The choice: keep these devices in one VLAN, or run an mDNS reflector / Bonjour gateway and do it properly.
Try this first
- 1List which devices need to be discovered from which VLAN, typically printers from staff and guest VLAN.
- 2On UniFi, Omada, Aruba: enable the mDNS repeater on the gateway, choose which VLANs reflect to which. Not all to all.
- 3For Sonos and Chromecast that rely on UPnP and SSDP: turn on UPnP relay or they stay invisible.
- 4Enable IGMP snooping on the switch so multicast is not flooded to every port, saves switch CPU and bandwidth.
- 5Test from a phone on the guest VLAN whether the printer shows up, not only from a laptop, since iOS is stricter on mDNS.
When to bring us in
You run latency-sensitive streaming (broadcast AV, IPTV, Dante audio): a generic mDNS reflector will not cut it, you need a real IGMPv3 plus querier setup with an AV partner.
See also
- Wi-Fi drops randomly across the officeFirst rule out whether it is the access points or the internet connection itself. Different fix.
- One room or corner has no or bad Wi-FiNot always "add another AP"; often one is poorly positioned, or there is a metal wall in the way.
- Internet is suddenly slow for everyoneThree suspects: your provider, a colleague soaking the line, or a backup or update kicking in unexpectedly.
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