I am using Yast on OpenSuse 12.1. When trying to install packages from the software repositories, I get an error that the repo cannot be accessed because the network is unreachable:
Download (curl) error for 'http://download.opensuse.org/update/12.1/repodata/repomd.xml': Error code: Connection failed Error message: Failed to connect to 2001:67c:2178:8::13: Network is unreachable
I tried accessing this URL in the browser, and it works fine.
This question suggests that the system date may have reset itself, but that is not the case for me. While it's a duplicate question, the accepted answer there is incorrect for me.