Pow has a special support for .xip.io domain[1]. If you add `export POW_EXT_DOMAINS=10.0.0.1.nip.io pow` to `~/.powconfig` it should work[2]. I haven't tried this myself though.

[1]: https://github.com/basecamp/pow/blob/master/lib/configuratio...

[2]: http://pow.cx/docs/configuration.html