TCP over lo

I've got a bug report about attempting to mount a remote NFSv4 server while the client's lo interface is down.

Apparently a TCP connection attempt over lo when it is DOWN results in ETIMEDOUT. If I attempt a TCP connect on eth0 when it is DOWN I get ENETUNREACH.

Is this behavior difference by design? Is there some other information I'm missing? Just wondering how to go about addressing the issue.

Thanks in advance for advice.

chuck[dot]lever[at]oracle[dot]com