This is definitely an upstream issue, but I think it's worth having it here and gather information from others.

Marian tried openshift with cdk today on our Windows laptop and the url generated for the app he deployed didn't work.
So I tried something simple like "ping 10.1.2.2.xip.io" from command line and it didn't work.
"ping xip.io" worked.

On my OS X laptop, this works as expected:

$ ping 10.1.2.2.xip.io
PING 10.1.2.2.xip.io (10.1.2.2): 56 data bytes
Request timeout for icmp_seq 0

Whereas on windows I only get:
Ping request could not find host 10.1.2.2.xip.io. Please check the name and try again.

I'm not sure if it's just a problem with our laptop, but it needs investigating in any case.