Bridged WLAN LAN Apple Multicast issue resolved

[G_W_Albrecht]

For more than a year now, i have experienced a strange limitation (see https://community.checkpoint.com/t5/SMB-Gateways-Spark/WLAN-to-LAN-internal-routing-issue/m-p/134154... for more details) concerning traffic between Apple devices on WLAN and Apple devices on LAN :

- screen sharing between two MacBooks in WLAN and LAN is not possible

- controlling iTunes on a MacBook in LAN with Remote App on iPhone (WLAN) is not possible

- printing or scanning from a MacBook in LAN on an Epson Printer in WLAN is not possible

I had studied Apple Bonjour before and knew that it uses Multicast, and i use a bridge to keep all devices in the same one network so we have no issues with network boundaries. But i realized that this was the right track when i found sk114596: Multicast traffic not forwarded over bridged interfaces on SMB appliances:

Cause

IGMP snooping is enabled "by default" on bridged interfaces. This feature is designed to prevent hosts on a local network from receiving traffic for a multicast group they have not explicitly joined. It provides switches with a mechanism to prune multicast traffic from links that do not contain a multicast listener (an IGMP client).

I had to create a file with the kernel parameter and all started to work as expected again 😀

I would suggest to either add information to sk114596 or, better, publish an own SK for this Apple Services issue !

[Chris_Atkinson]

Nice find.

Was feedback submitted for the original SK?

What additional steps did you implement? 

[G_W_Albrecht]

1. Directly communicated this to Amir Ayalon; Dafna Mozel; Oleg Umanets ; Zachi Schnieder

2. gave feedback for version:

Your feedback was:
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This is not relevant for R80.20.xx SMBs ? kind regards, -- Guenther Albrecht Arrow ECS Internet Security AG A-1100 Wien, Wienerbergstrasse 11 Tel: 43 1 370 94 40 325 Fax: 43 1 370 94 40-333
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This feature is not included in the product.

If you need it, please submit a Request for Enhancement.

3. No additional steps were needed - all worked as expected then.

[Chris_Atkinson]

To clarify there was a separate kernel parameter you used that doesn't feature in the current SK?

[G_W_Albrecht]

No, the current SK is the solution - but the sk114596 only is for version R77.20.xx and does not mention Apple Bonjour nor the symptoms:

- screen sharing between two MacBooks in WLAN and LAN is not possible

- controlling iTunes on a MacBook in LAN with Remote App on iPhone (WLAN) is not possible

- printing or scanning from a MacBook in LAN on an Epson Printer in WLAN is not possible

As a CCSP, i had 3 customers already that had such a Bonjour issue, and only one had found the SK (but not tried the solution yet).