Loopback to different 127.*.*.* ips mac osx

You can't bind to the loopback interface automatically on mac osx.

> rails -b 127.0.0.2
ERROR: Can't assign requested address - bind(2) for 127.0.0.2:3000 (Errno::EADDRNOTAVAIL)

Mac OSX will disable all loopback addresses other than 127.0.0.1 by default, but they can be enabled with ifconfig.

> sudo ifconfig lo0 alias 127.0.0.2 up

And now your server can bind to that address.

h/t Jack Christensen

Tweet