On an android device, I am connecting to a remote network using openvpn for performing service discovery.

1. WORKING CASE: After the device is camped on 3g/4g and after connecting to remote network by openvpn, when the zeroconf browser is launched, I can see the mdns query packets being send through the tap0 interface resulting into rendering of services on the browser.

From the tcpdump captured on the device, I can see that the mdns query packets are send to tap0 interface.

tap0 ip: 192.168.11.200

Route table information: Destination Gateway Genmask Flags Metric Ref Use Iface 76.26.112.234 10.179.240.1 255.255.255.255 UGH 0 0 0 pdpbr1 10.179.240.1 * 255.255.255.255 UH 0 0 0 pdpbr1 32.1.72.136 * 255.255.255.255 UH 0 0 0 pdpbr0 10.179.240.0 * 255.255.255.0 U 0 0 0 pdpbr1 192.168.11.0 * 255.255.255.0 U 0 0 0 tap0 default 192.168.11.1 0.0.0.0 UG 0 0 0 tap0

1. NOT WORKING CASE: However, after switching on the wifi and connecting it to remote network, when the zeroconf browser is launched, instead of sending the mdns query packets to tap0 interface; these packets are being send to eth0 interface due to which we cannot see the services.

From the tcpdump captured on the device, I can see that mdns query packets are send to eth0 interface.

tap0 ip: 192.168.11.200 eth0 ip: 192.168.43.230

route table information: Destination Gateway Genmask Flags Metric Ref Use Iface 76.26.112.234 192.168.43.1 255.255.255.255 UGH 0 0 0 eth0 32.1.72.136 * 255.255.255.255 UH 0 0 0 pdpbr0 192.168.11.0 * 255.255.255.0 U 0 0 0 tap0 192.168.43.0 * 255.255.255.0 U 0 0 0 eth0 default 192.168.11.1 0.0.0.0 UG 0 0 0 tap0

In the above case, even though there is a default route for tap0, all the multicast packets are being routed through eth0. How is this possible?

Has anyone observed a similar problem and it would be really helpful if you can help us to discover services through zeroconf browser after the device is connected to remote network via openvpn through wifi.

Thank You Very much, Mrunal