ProxyPass to internal host and custom unavailability message

Question

I have a school server which is accessible from the internet under certain domain name. I managed to establish a proxy pass to a host from internal local network so as to make library OPAC available:

ProxyPass /library/ 10.0.5.5

It works fine, but I'd like to be able to detect if this host is running (it does not work 24/7) and if not, display a message, so that users don't get confused with "Cannot reach server" error.

Can I accomplish this only using only Apache directives?

Answer 1

You can use ErrorDocument 503 "Message Here"

You can also put in a custom HTML document. See the documentation here: http://httpd.apache.org/docs/current/custom-error.html