A very weird behavior on a MBP. It seems that some websites are now advertising Ipv6 addresses (e.g., www.doodle.com, addons.mozilla.org, etc.).
For some reason, even though I only have an Ipv4 address on the network, Firefox and Safari are trying to connect to the Ipv6 addresses, which of course fails. Even trying telnet to port 80 of those hostnames results in a an attempt to connect via Ipv6. It seems like this problem started around mid-December.
Here's an example:
$ telnet www.doodle.com 80 Trying 2a02:d58:2001::72... Connected to doodle.com. Escape character is '^]'.
Connection closed by foreign host. $