HTTP Headers

HTTP headers are a list of strings sent and received by both the client and server on every Hypertext Transfer Protocol (HTTP) request and response. This section describes HTTP headers supported by HTTP and HTTP listeners.

**Table 1** Transfer headers
Header	Feature	Description	Dedicated Load Balancers
X-Forwarded-ELB-IP	Transfer Load Balancer EIP	If this option is enabled, the EIP bound to the load balancer will be transmitted to backend servers through the X-Forwarded-ELB-IP header. The format is as follows (XX.XXX.XX.XXX indicates the EIP of the load balancer): X-Forwarded-ELB-IP: XX.XXX.XX.XXX	Supported
X-Forwarded-ELB-ID	Transfer Load Balancer ID	If this option is enabled, the load balancer ID will be transmitted to backend servers through the X-Forwarded-ELB-ID header.	Supported
X-Forwarded-Port	Transfer Listener Port Number	If this option is enabled, the port number used by the listener will be transmitted to backend servers through the X-Forwarded-Port header.	Supported
X-Forwarded-For-Port	Transfer Port Number in the Request	If this option is enabled, the port number used by the client will be transmitted to backend servers through the X-Forwarded-For-Port header.	Supported

**Table 2** Rewrite headers
Header	Feature	Description	Dedicated Load Balancers
X-Forwarded-Host	Rewrite X-Forwarded-Host	If this option is enabled, the Host header of the client request will be rewritten into the X-Forwarded-Host header and transmitted to the backend servers. If this option is disabled, the X-Forwarded-Host header of the client will be transmitted to the backend servers.	Supported
X-Forwarded-Proto	Rewrite X-Forwarded-Proto	If this option is enabled, the listener protocol will be rewritten into the X-Forwarded-Proto header field and transmitted to the backend servers. If this option is disabled, the protocol used by the client will be transmitted to the backend servers through the X-Forwarded-Proto header.	Supported
X-Real-IP	Rewrite X-Real-IP	If this option is enabled, the source IP address of the client will be rewritten into the X-Real-IP header and transmitted to the backend servers. If this option is disabled, the X-Real-IP header of the client will be transmitted to the backend servers.	Supported

More HTTP headers are coming soon. See the available HTTP headers on the management console.
√ indicates the load balancer supports the header, whereas × indicates the load balancer does not support the header.

Enabling HTTP/HTTPS Headers

Go to the load balancer list page.
You can enable these header features in either of the following ways:
- On the displayed page, locate the load balancer and click its name. Under Listeners, click Add Listener.
- On the displayed page, locate the load balancer and click Add Listener in the Operation column.
On the Configure Listener page, expand Advanced Settings and enable the features as needed.
Configure the listener as prompted.
Confirm the configuration and click Submit.

Modifying HTTP Header Features

Go to the load balancer list page.
On the displayed page, locate the load balancer and click its name.
Click the Listeners tab, locate the target listener and click Edit in Operation column.
On the displayed page, expand Advanced Settings and enable or disable the features.
Click OK.