req.host
This method is deprecated and will likely be removed or changed in an upcoming release.
Instead, use req.hostname.
The hostname of this request, without the port number, as specified by its "Host" header.
req.host;
If this request's "Host" header was "ww3.staging.ibm.com:1492":
req.host;
// -> "ww3.staging.ibm.com"