XFF headers supported in OJS 2.4.x

Thanks Curtis, I just stumbled across this in the config file. Here are the questions please.

  1. Do XFF headers work?
  2. Is there a security issue setting trust_x_forwarded_for = on ??
  3. The default statement of “on” seems inaccurate for 2.4.x installs as we did not know it was there.
  4. Does enabling it break something else?
  5. Is there a way to be emailed when someone access the system via this mode?
    Our section of config.

; Allow the X_FORWARDED_FOR header to override the REMOTE_ADDR as the source IP
; Set this to “On” if you are behind a reverse proxy and you control the X_FORWARDED_FOR
; Warning: This defaults to “On” if unset for backwards compatibility.
trust_x_forwarded_for = Off

Many Thanks!
radjr