Parameter | Description |
Enable OCSP Stapling | Specifies whether to enable the Online Certificate Status Protocol (OCSP) stapling feature. Important This feature is available only for a website service that supports HTTPS. If HTTPS is selected for Protocol Type, we recommend that you enable this feature. OCSP is an Internet protocol that is used by a Certificate Authority (CA) to check the revocation status of a certificate. When a client initiates a TLS handshake with a server, the client must obtain the certificate and an OCSP response. The OCSP stapling feature is disabled by default. In this case, OCSP queries are sent from a browser of the client to a CA. Before the client obtains an OCSP response, subsequent events are blocked. If transient connections or network disconnections occur, a blank page is displayed for a long period of time, and the performance of the website that supports HTTPS is compromised. If the OCSP stapling feature is enabled, Anti-DDoS Proxy executes OCSP queries and caches the query results for 3,600 seconds. When a client initiates a TLS handshake with the server, Anti-DDoS Proxy returns the OCSP details and the certificate chain to the client. This prevents blocking issues caused by OCSP queries from the client. OCSP does not cause security risks because OCSP responses cannot be forged.
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Cookie Settings | Delivery Status By default, the delivery status is enabled. When enabled, Anti-DDoS Proxy inserts cookies into the client of your website, such as a browser, to distinguish your client from other clients, or to obtain information such as client fingerprints. For more information, see Configure the HTTP flood mitigation feature. Important If you want to stop the Anti-DDoS Proxy from inserting cookies into your service, you can turn off the switch. However, disabling this option will prevent the Anti-DDoS Proxy from actively assessing and defending against HTTP flood attacks through the HTTP flood mitigation rules. Secure Attribute The Secure attribute is disabled by default. If enabled, cookies will only be delivered over HTTPS connections, not over HTTP connections, which helps protect cookies from being stolen by attackers. We recommend enabling this option if your website only supports HTTPS connections.
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Traffic Marking | Originating Port The name of the HTTP header that contains the originating port of the client. In most cases, the X-Forwarded-ClientSrcPort header is used to record the originating port of the client. If you use a custom header to record the originating port of the client, specify the custom header for Originating Port. After Anti-DDoS Proxy forwards back-to-origin requests to your origin server, your origin server parses the custom header to obtain the originating port of the client. The steps to obtain the originating port of the client are similar to the steps to obtain the originating IP address of the client. For more information, see Obtain the originating IP addresses of requests. Originating IP Address The name of the HTTP header that contains the originating IP address of the client. In most cases, the X-Forwarded-For header is used to record the originating IP address of the client. If you use a custom header to record the originating IP address of the client, specify the custom header for Originating IP Address. After Anti-DDoS Proxy forwards back-to-origin requests to your origin server, your origin server parses the custom header to obtain the originating IP address of the client. Custom Header You can add custom HTTP headers to requests that pass Anti-DDoS Proxy to mark the requests. To add custom HTTP headers, specify header names and values. After you create custom headers, Anti-DDoS Proxy adds the custom headers to the back-to-origin requests. This way, the backend servers can perform statistical analysis on the back-to-origin requests. Do not use the following default headers as custom headers: X-Forwarded-ClientSrcPort : This header is used to obtain the originating ports of clients that access Anti-DDoS Proxy (a Layer 7 proxy).
X-Forwarded-ProxyPort : This header is used to obtain the ports of listeners that access Anti-DDoS Proxy (a Layer 7 proxy).
X-Forwarded-For : This header is used to obtain the originating IP addresses of clients that access Anti-DDoS Proxy (a Layer 7 proxy).
Do not use standard HTTP headers (such as Host, User-Agent, Connection, and Upgrade) or widely-used custom HTTP headers (such as X-Real-IP, X-True-IP, X-Client-IP, Web-Server-Type, WL-Proxy-Client-IP, EagleEye-RPCID, EagleEye-TraceID, X-Forwarded-Cluster, and X-Forwarded-Proto). If you use the above headers, the original headers are overwritten. You can add up to five custom HTTP headers.
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Back-to-origin Scheduling Algorithm | The load balancing algorithm for back-to-origin requests. If multiple origin server addresses are configured, this parameter is required. The origin server addresses can be IP addresses or domain names. You can change the load balancing algorithm for back-to-origin requests or specify weights for the server addresses. IP hash: If you select this option, you can specify weights for the origin servers. The IP hash option allows requests from a specific client to be forwarded to the same origin server within a period of time. This ensures session consistency. You can specify a higher weight for an origin server that has better performance. This way, the high-performance origin server can process more requests, and resource utilization is optimized. Round-robin: If you select this option, all requests are distributed to the origin servers in turn. By default, all origin servers have the same weight. You can change the weights of the origin servers. The higher the weight of the origin server, the higher the possibility that back-to-origin requests are forwarded to the origin server. Least time: If you select this option, the system uses intelligent Domain Name System (DNS) resolution and the least-response-time algorithm to reduce latency when requests are forwarded to the origin servers.
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Other Settings | Configure New Connection Timeout Period: the timeout period for establishing a connection. If Anti-DDoS Proxy fails to establish a connection to the origin server within the specified timeout period, the connection request fails. Valid values: 1 to 10. Unit: seconds. Configure Read Connection Timeout Period: the timeout period for processing a read request. If the origin server fails to respond to a read request sent by Anti-DDoS Proxy over the established connection within the specified timeout period, the read request fails. Valid values: 10 to 300. Unit: seconds. Configure Write Connection Timeout Period: the timeout period for processing a write request. If Anti-DDoS Proxy fails to send all data to the origin server or the origin server fails to start processing the data within the specified timeout period, the write request fails. Valid values: 10 to 300. Unit: seconds. Retry Back-to-origin Requests: If you turn on the switch and the resource requested by Anti-DDoS Proxy cannot be retrieved from the cache server, the cache server retrieves the resource from the upper-level cache server or the origin server. Back-to-origin Persistent Connections: If you turn on the switch, the TCP connection between the cache server and the origin server remains active for a period of time. The connection is not closed every time a request is complete. This helps reduce the time and resource required to establish a connection and improve the efficiency and speed of request processing. Requests Reusing Persistent Connections: the maximum number of HTTP requests that Anti-DDoS Proxy can send to the origin server over a TCP connection. The use of persistent connections helps reduce latency and resource consumption that are caused when you frequently establish and close connections. Valid values: 10 to 1000. We recommend that you specify a value less than or equal to the number of requests reusing persistent connections that is configured on the origin server, such as a WAF or SLB instance. This helps prevent service unavailability due to persistent connection failures. Timeout Period of Idle Persistent Connections: the timeout period for an idle persistent TCP connection that Anti-DDoS Proxy establishes to the origin server. If data is not transmitted over an open TCP connection in the connection pool of Anti-DDoS Proxy, the TCP connection is considered idle. If no new requests are initiated over the idle TCP connection within the specified timeout period, the connection is closed to release system resources. Valid values: 10 to 30. Unit: seconds. We recommend that you specify a value less than or equal to the timeout period configured on the origin server, such as a WAF or SLB instance. This helps prevent service unavailability due to persistent connection failures. Upper Limit for HTTP/2 Streams: the maximum number of HTTP/2 streams that are allowed on the server. This feature is available only when HTTP/2 is used. Valid values: 16 to 32. If you want to specify a larger value, contact your account manager.
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