When Safari can't resolve IPv6 DNS lookups, the URL bar is extremely slow

Originator:thomas
Number:rdar://31961971 Date Originated:5/3/17
Status:open Resolved:
Product:macOS + SDK Product Version:10.12.4 (16E195)
Classification:Serious Bug Reproducible:Always
 
Area:
Safari

Summary:
After typing a URL in the URL bar and hitting Enter Safari just sits there and doesn't nothing for 10-20 seconds. After that the page loads normally.

Steps to Reproduce:
1. Have IPv6 auto configured, but the network not support it
2. Type a URL that hasn't been locally cached in the Safari URL bar
3. Press the Enter key

Expected Results:
Page loads more or less immediately

Actual Results:
There's a 10-20 second delay before the page loads.

Version:
10.12.4 (16E195)

Notes:
Turning off IPv6 seems to solve the problem:

$ networksetup -setv6off "Wi-Fi"

I've tried clearing Safari caches completely, and the obvious reboots, but that didn't change anything.

I'm on a Unifi Wi-Fi network, with a Comcast Business internet connection. Other browsers, like Chrome and Firefox do not exhibit this problem.

Configuration:
MacBook Pro (13-inch, 2016, 4 Thunderbolt 3 Ports)

Comments


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