MacBook Pro sleep causes network failure

A short time ago, my MacBook Pro developed a new and annoying habit. After putting it to sleep by closing the clamshell, and then waking it, the WiFi network wasn’t working.

Safari would report “You are not connected to the Internet” and DNS queries via dig in Terminal would fail with an “Unknown host” error message.  Interestingly enough, ifconfig reported that I did in fact have an IP address:


ether 60:33:4b:XX:YY:ZZ

inet6 fe80::6233:4bff:fe0a:d552%en1 prefixlen 64 scopeid 0x5

inet netmask 0xffffff00 broadcast

media: autoselect

status: active

And netstat reported that I had a default route which pointed at my default network gateway:

$ netstat -rn

Routing tables


Destination        Gateway            Flags        Refs      Use   Netif Expire

default             UGSc            7        0     en1

10.0.1/24          link#5             UCS             4        0     en1

Upon further examination, I was also able to ping the default gateway. And I was able to send DNS queries (dig @ syntax) to the gateway and get them resolved. But attempts to resolve hosts using Snow Leopard’s DNS recursion failed.

The workaround was turning WiFi off and then back on. Voila, problem solved until the next time I put my laptop so sleep. Today I decided to find and fix the problem. The solution was disabling IPv6 support on the WiFi network interface (in Network control panel). Voila, problem solved.