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iPad : Bonjour Services

Both my iPhone XR & iPad started using a new Bonjour service that they never used before.


Service Name: _rdlink._tcp.

Port(same for both): 49153


On top of that iPad is using another service called _companion-link._tcp and using 49154 as the port. Was not sure why both would be activated


Both devices have been freezing/slowing down for a while hence I was afraid if there might be a security concern.


i would appreciate if someone can help.


Best

Burak


iPad Pro, iPadOS 15

Posted on Apr 15, 2022 2:48 PM

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Question marked as Top-ranking reply

Posted on Apr 16, 2022 12:56 PM

Hello se7enthsense,


We'd be happy to research this with you. Can you please tell us exactly where you're seeing this information on your devices? Also, what versions of iOS 15 do you currently have installed? This is in Settings > General > About.


Doing a bit of digging, we were able to find an article that discusses Bonjour and what its purpose is. Please review the article below for full details.


Bonjour discovery - Apple Support


Hope you find this helpful!


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Apr 16, 2022 12:56 PM in response to se7enthsense

Hello se7enthsense,


We'd be happy to research this with you. Can you please tell us exactly where you're seeing this information on your devices? Also, what versions of iOS 15 do you currently have installed? This is in Settings > General > About.


Doing a bit of digging, we were able to find an article that discusses Bonjour and what its purpose is. Please review the article below for full details.


Bonjour discovery - Apple Support


Hope you find this helpful!


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Apr 16, 2022 8:31 PM in response to Missy5937

Hey,


I see it on “NetAnalyzer” app on my iPhone & iPad. The application shows you the Bonjour & uPNP used by devices connected to your network and this service is listed for both my iPhone & iPad.

I am using the latest iOS version (15.4.1)


Hope you would be able to help.


Thanks

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Apr 17, 2022 2:20 AM in response to Missy5937

that link is not really helpful. I see the rdlink too


-  wlan0 IPv6 louis iphone                                  _rdlink._tcp         local


I am curious to know as well what it means. Typically it is the protocol used over tcp e.g. http. I cannot find any info in the internet.

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Apr 17, 2022 8:16 AM in response to se7enthsense

Ports within the 49152-65535 range are dynamically assigned to services as and when required. Dynamically assigned porte are quite literally “dynamic” in that they are assigned as required - and port numbers for any specific service may differ between networks and devices.


Unless you have specific connectivity issues that require diagnosis with a protocol analyser (and have appropriate network skills to do so), other than as curiosity, specific high-port assignment is of little interest beyond that of mere curiosity.


The linked article concerning Bonjour Discovery provides much of the technical detail concerning functioning of Bonjour and its associated core protocols/services.

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Apr 17, 2022 11:06 AM in response to LotusPilot

Thank you for taking your time to share the common knowledge on the subject. I wouldn’t have raised this question if that information was satisfactory which I thought was very clear from my messages.


I am seeing a Bonjour service actively available on both WIFI & cellular which was not available ever before. And there is no information online so yes I would like to know more to ensure there is no security concern.



[Edited by Moderator]

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Apr 17, 2022 11:19 AM in response to se7enthsense

Assuming that you have access to a PC and a suitable network hub (not a network switch) with which you can sniff network traffic, I recommend that you run a full packet trace analysis with suitable packet capture software - such as Wireshark. This should allow you to identify the host devices between for which the traffic of which you have interest is exchanged.


As mDNS (Bonjour) traffic is limited to your local subnet, you have no concerns for security.

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iPad : Bonjour Services

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