Article Number: 000142540
Apple Bonjour and Multiple VLANs Limits on Dell Networking Switches
Summary: This article discusses the limitations Bonjour protocol (AirPrint and AirPlay) and multicast routing on Dell Networking Switches.
Article Content
Symptoms
This article discusses the limitations Bonjour® protocol on Dell Networking Switches. Services that use Bonjour include Apple® AirPrint and AirPlay.
Bonjour is a zero configuration networking enables service discovery, address assignment, and name resolution for desktop computers, mobile devices, and network services. It is designed for flat, single-subnet IP networks such as wireless networking at home. Bonjour is the trade name for the zero configuration implementation introduced by Apple. It is supported by most of the Apple product lines, including the Mac OS X operating system, iPhone, iPod Touch, iPad, Apple TV, and AirPort Express.
Bonjour can be installed on computers running Microsoft Windows® and is supported by the new network-capable printers (AirPrint). Bonjour is also included with popular software programs such as Apple Photos, iTunes, and Safari. Bonjour uses multicast DNS (mDNS) to locate devices and the services offered by these devices.
Dell Networking switches are compliant with industry standard RFC6762 for Bonjour. Bonjour uses link-local multicast, similar to a broadcast packet. Link-local multicast is allowed and enabled by default on Dell Networking switches; no configuration is needed. However, it is recommended to disable igmp snooping, as igmp snooping can lead to dropped link-local multicast traffic.
To disable igmp snooping globally on N-Series:
N3000(config)#no ip igmp snooping
To disable igmp snooping on S-Series:
S3000(config)#no ip igmp snooping enable
Bonjour is designed for flat, single-VLAN, single-subnet IP networks, per RFC6762.
Dell Networking switches do not support routing Bonjour across multiple VLANs.
Some Dell Networking switches support multicast routing, however Bonjour is incompatible with RFC compliant multicast routing. Bonjour uses mDNS. mDNS uses a link-local ip address, per RFC6762: "Any DNS query for a name ending with ".local." MUST be sent to the mDNS IPv4 link-local multicast address 224.0.0.251." 224.0.0.251 is a link local multicast addresses. Local addresses cannot be routed.
Some vendors have implemented custom mDNS bridging across subnets, to allow Bonjour to work with multiple VLANs and subnets. This workaround is not a feature of Dell Networking switches, and it breaks RFC compliance.
What is Bonjour?
Bonjour is a zero configuration networking enables service discovery, address assignment, and name resolution for desktop computers, mobile devices, and network services. It is designed for flat, single-subnet IP networks such as wireless networking at home. Bonjour is the trade name for the zero configuration implementation introduced by Apple. It is supported by most of the Apple product lines, including the Mac OS X operating system, iPhone, iPod Touch, iPad, Apple TV, and AirPort Express.
Bonjour can be installed on computers running Microsoft Windows® and is supported by the new network-capable printers (AirPrint). Bonjour is also included with popular software programs such as Apple Photos, iTunes, and Safari. Bonjour uses multicast DNS (mDNS) to locate devices and the services offered by these devices.
Configuring Bonjour on Dell Networking
Dell Networking switches are compliant with industry standard RFC6762 for Bonjour. Bonjour uses link-local multicast, similar to a broadcast packet. Link-local multicast is allowed and enabled by default on Dell Networking switches; no configuration is needed. However, it is recommended to disable igmp snooping, as igmp snooping can lead to dropped link-local multicast traffic.
To disable igmp snooping globally on N-Series:
N3000(config)#no ip igmp snooping
To disable igmp snooping on S-Series:
S3000(config)#no ip igmp snooping enable
Limitations of Bonjour on Dell Networking
Bonjour is designed for flat, single-VLAN, single-subnet IP networks, per RFC6762.
Dell Networking switches do not support routing Bonjour across multiple VLANs.
Some Dell Networking switches support multicast routing, however Bonjour is incompatible with RFC compliant multicast routing. Bonjour uses mDNS. mDNS uses a link-local ip address, per RFC6762: "Any DNS query for a name ending with ".local." MUST be sent to the mDNS IPv4 link-local multicast address 224.0.0.251." 224.0.0.251 is a link local multicast addresses. Local addresses cannot be routed.
Some vendors have implemented custom mDNS bridging across subnets, to allow Bonjour to work with multiple VLANs and subnets. This workaround is not a feature of Dell Networking switches, and it breaks RFC compliance.
Article Properties
Affected Product
PowerSwitch S3048-ON, PowerSwitch S4048-ON, PowerSwitch S4810-ON, PowerSwitch S5000, PowerSwitch S6000, PowerSwitch S6000 ON, PowerSwitch N1500 Series, PowerSwitch N2000 Series, PowerSwitch N2100 Series, PowerSwitch N3000 Series
, Dell EMC PowerSwitch N3100 Series, PowerSwitch N4000 Series, PowerSwitch S4048T-ON, PowerSwitch S6010-ON, PowerSwitch S6100-ON, Dell Networking X1000 Series, Dell Networking X4000 Series
...
Last Published Date
10 Apr 2021
Version
3
Article Type
Solution