Meteor ROOT_URL setting to make accounts-facebook work when behind apache proxy -

i'm running meteor on localhost:3000 , have apache set proxy requests domain meteor instance using virtualhost , mod_proxy.

i'm getting error when trying log in meteor app using accounts-facebook:

given url not allowed application configuration.: 1 or more of given urls not allowed app's settings. must match website url or canvas url, or domain must subdomain of 1 of app's domains.

i think because root_url http://localhost:3000 . if change root_url domain, of course meteor tries listen domain, can't because apache server in way.

is there way can make work without ip address?

from meteor documentation,

ensure $root_url matches authorized domain , callback url configure external service (for instance, if running meteor behind proxy server, $root_url should externally-accessible url, not url inside proxy).

in case, app listening on configured port mod_proxy behind apache proxy server, listening http://www.example.com:8080. have other applications running on other ports.

to going, on facebook set site url , valid oauth redirect uris http://www.example.com:3000 , app domains www.example.com. on machine set root_url http://www.example.com:3000, externally-accessible.

such configurations work me without second ip address.