Open Radar

 
Summary:
mDNS doesn't always communicate over WiFi IPv4 interfaces on iOS devices.  I've setup a network where an iPad and a Windows 7 PC running iTunes is connected to an Access Point that does not provide DHCP.  In this scenario, both the iPad claims a link-local address for both IPv4 and IPv6.  The Windows 7 machine claims a link-local for both IPv4 and IPv6 as well.

If I launch the Remote app on the iPad, iTunes never detects the Remote mDNS service in order to display the "remote" button that allows the pairing.

If I do a wireshark capture of the network traffic, I can see the iPad is communicating mDNS over IPv6, but not IPv4.  I can also see iTunes only communicating over IPv4

Steps to Reproduce:
1. Connect iPad to network with no DHCP
2. Connect Windows 7 computer running iTunes to network
3. Launch Remote app on iPad
4. iTunes will never detect the Remote app

Expected Results:
I expect mDNS to communicate over IPv4 and IPv6 at all times in accordance with mDNS RFC (http://tools.ietf.org/html/rfc6762#page-52)

I would expect iTunes on the PC to detect the Remote app on the iPad

Actual Results:
mDNS on iPad only communicates over IPv6 in certain circumstances and this means the remote app isn't detected from iTunes

Version:
iOS 7.0.6 (11B651)
iPad MC980LL/A

Notes:
Attached is a wireshark capture of the iPad (IPv6 address fe80::14b7:a36f:1f2d:532d) and Windows PC, (IPv4 address 169.254.121.125)

Configuration:
iPad 2
Windows 7 service pack 1
iTunes 11.1.4.62
Access Point with DHCP disabled