I have a service which registers with AVAHI on Linux and DNS-SD when running on Macs. When browsing for the service on a Mac I find that the service registered with AVAHI behaves differently to the same service registered with DNS-SD on Macs.
This can lead to the AVAHI entry becoming unlisted while the Mac entries remain listed fine. The context is this: On Macs it is possible to give all the computer's network interfaces the same IP address. This does not result in a conflict because it is possible to give the interfaces a hierarchical priority, e.g. to give the 1000baseT i/f top priority but if it is not connected and running to then fall back to Wifi. In that priority scenario, if the 1000baseT i/f is connected (with the Wifi i/f also running but not being used due to its lower priority), the service listing or the other Macs is added for the Ethernet and listed as being available on both interfaces. If the 1000baseT cable is removed, the service is removed from that i/f but not the Wifi as it is still running (and the Wifi i/f then becomes the prime interface again). However the AVAHI-registered service does not get added at the point that the Ethernet is connected, it remains listed for the Wifi i/f only. Disabling Wifi causes its listing for that i/f to be removed, meaning that host's service no longer has any listing at all. Sometimes disabling Wifi provokes the AVAHI-registered service to be added for the Ethernet, sometimes it remains with no listing at all as is shown in the capture below. The services were registered with "avahi-publish -s raspi _test._tcp 1234" and "dns-sd -R mini _test._tcp . 1234". Here the Ethernet has i/f index 4 and Wifi i/f index 5. Both mini and raspi are on the same LAN as are the client computer's Wifi and Ethernet interfaces. [macbook:~] me% dns-sd -B _test._tcp Browsing for _test._tcp DATE: ---Fri 21 Feb 2014--- 22:15:40.473 ...STARTING... Timestamp A/R Flags if Domain Service Type Instance 22:15:40.473 Add 3 5 local. _test._tcp. mini 22:15:40.473 Add 3 5 local. _test._tcp. raspi 22:15:40.473 Add 3 4 local. _test._tcp. raspi 22:15:40.473 Add 2 4 local. _test._tcp. mini ^^^^ start: Wifi on, Ethernet on, services shown for Mac Mini and Raspberry Pi for both interfaces 22:16:01.564 Rmv 1 4 local. _test._tcp. raspi 22:16:01.564 Rmv 0 4 local. _test._tcp. mini ^^^^ disconnect Ethernet, service removed for mini and raspi 22:16:22.889 Add 2 4 local. _test._tcp. mini ^^^^ connect Ethernet, service added for mini but NOT raspi 22:16:52.132 Rmv 1 5 local. _test._tcp. mini 22:16:52.132 Rmv 0 5 local. _test._tcp. raspi ^^^^ disable Wifi, service removed for mini and raspi, now no service listed at all for raspi 22:17:44.173 Rmv 0 4 local. _test._tcp. mini ^^^^ disconnect Ethernet, mini removed but no raspi entry to remove 22:17:53.001 Add 2 4 local. _test._tcp. mini ^^^^ connect Ethernet, back come both hosts 22:17:53.025 Add 2 4 local. _test._tcp. raspi 22:18:10.989 Add 2 5 local. _test._tcp. raspi ^^^^ enable Wifi, back come both hosts 22:18:11.052 Add 2 5 local. _test._tcp. mini Is this a configuration issue, a bug, or just different behaviour within the spec? Is there a way to get the AVAHI service to behave the same way as the DNS-SD one? _______________________________________________ avahi mailing list avahi@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/avahi
