ping localhost doesn't work in a vfkit vm?

[rjkroege]

Describe the bug
I create a Linux vm using vfkit on an Apple Silicon Mac. I booted such a vm using the test puipui kernel from Code-Hex/vz: Create virtual machines and run Linux-based operating systems in Go using Apple Virtualization.framework. and an initrd build with u-root.

To Reproduce
Boot the vm. ping 127.0.0.1. Note the following unexpected output

% ping 127.0.0.1
64 bytes from 127.0.0.1: icmp_seq=1 time=75.875µs
1970/01/01 00:01:38 ping failed: got seq 1; want 2

Expected behavior
I expect ping 127.0.0.1 to indicate that it's connected. For example, if I boot the puipui kernel (same kernel as above) with its associated initrd,

~ # ping 127.0.0.1
127.0.0.1 is alive!

So: ping from busy box works as expected while u-root ping does not where kernel, vm and vm launch configuration are held constant.

Conclusion: there is something not-right happening with my u-root to setup the network. Any helpful comments would be appreciated. Otherwise, I will continue to explore this and update the bug.

[binjip978]

Yeah, this is a problem with u-root ping, this can be reproduced on any machine, you don't need a VM. To make it work on localhost is more tricky. It will work with -c=1 but no more.

[rjkroege]

Ah. Thanks for the update.

I should probably note in passing that I discovered this bug while trying to make the network work in my vm and stopped at "if I can't even get ping to localhost to work, then there's no hope for more general networking"