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My Mac (OSX 10.12.3) cannot find local Bonjour (mdns) services - e.g. local Mac computers, Apple TVs etc.
When using "Bonjour Browser" (http://www.tildesoft.com/) I can see:
- Services from an iCloud space (962?????.members.btmm.icloud.com)
- No services from the "local" space.
Using Wireshark I can see mdns packets arriving at en0 interface (wifi), so the local mdns data is being received, but for some reason the mDNSResponder is not capturing it and making it locally available.
(Note: my iPhone on the same wifi network can see local services.)
Any ideas on where/how to start resolving this problem?
(UPDATE: 2 Feb) After more digging, I've enabled mdnsResponder logging and found the following when attempting to resolve .local addresses:
2017-02-02 11:54:10.364202+0000 localhost mDNSResponder[6047]: [com.apple.mDNSResponder.AllINFO] setsockopt - IP_MULTICAST_IF error 192.168.1.78 -1 errno 9 (Bad file descriptor) 2017-02-02 11:54:10.364405+0000 localhost mDNSResponder[6047]: [com.apple.mDNSResponder.AllINFO] setsockopt - IPV6_MULTICAST_IF error -1 errno 0 (Undefined error: 0)
I don't see this on other (working) Macs when attempting to resolve a .local address.
Frank Taylor
Posted 2017-01-30T15:38:33.303
Reputation: 1
Does rebooting make a difference? – Spiff – 2017-01-31T06:04:56.710
No. This problem has been with me for several months. – Frank Taylor – 2017-01-31T17:39:02.687
If you ping 224.0.0.1 (the "all hosts" multicast address) from another host on the network, does your Mac reply? (Make sure you haven't set your personal firewall to block pings before you test this) – Spiff – 2017-01-31T17:46:10.323
Yes. I can see on Wireshark on the Mac that the ping comes in and the reply is sent back. However I also see an ICMP from 10.128.128.128 indicating "Destination unreachable (Communication Administratively Filtered)". This is a clue. – Frank Taylor – 2017-02-01T13:42:43.330
Is the Mac running VPN software? Some full tunnel VPN products force all traffic to obey VPN rules, and can even block things like AirDrop and AirPlay. – Spiff – 2017-02-01T15:30:52.080
Thanks for following up. Yes I do run a VPN, but i get the failure when the VPN is connected and also when its not connected. I even get the failure when the machine is fresh booted and before I've connected to the VPN.
The 10.X.X.X is an internal address normally accessed over the VPN. However I see Destination Unreachable ICMPs from 10.128.128.128 even when the VPN is not connected.
I wonder if the VPN has configured something on my Mac which it has not tidied up. It is the Palo Alto Networks GlobalProtect.
No idea where to look next. – Frank Taylor – 2017-02-01T15:54:43.783
Further update. When at home, pinging 224.0.0.1 from another machine seems to work correctly. I see the ping request/reply on the Mac and no ICMPs indicating delivery failures. However Bonjour is still not listing any local services. – Frank Taylor – 2017-02-02T11:56:02.643