Mac OS X 10.10: dns resolver often doesn't update after wifi network change

Originator:aufflick
Number:rdar://18437119 Date Originated:24-Sep-2014 04:52 PM
Status:Open Resolved:
Product:OS X Product Version:Mac OS X 10.10 (14A361c)
Classification:Serious Bug Reproducible:Sometimes
 
Summary:
Sometimes when I change wifi networks, the new IP network is connected correctly (ie. the DHCP address, default route etc. are honoured), but the system resolver remains pointing to the DNS server address(es) of the prior network.

Steps to Reproduce:

1. be on wifi network A
2. put macbook to sleep
3. physically move to where wifi network B is
4. wake macbook up

NB: I’m not sure that a sleep/wake cycle is required, but I haven’t noticed the problem without it (although of course changing wifi networks in-situ is much less common so that’s not too surprising)

Expected Results:

The new wifi DHCP responses are honoured for both IP and DNS.

Actual Results:

The new wifi DHCP responses are honoured for IP only, not DNS.

ie. browser won’t work to go to google.com, but “ping 74.125.237.136” is successful. Also, “cat /etc/resolv.conf” shows the DNS server(s) for wifi network A.

Regression:

Worked fine in 10.9, not entirely sure if it behaved this way in prior 10.10 betas or not.

Notes:

Turning wifi on and off again on macbook fixes the problem, so I’m pretty sure it’s not a bad DHCP server.

Comments


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