> For the complete documentation index, see [llms.txt](https://docs.link11.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.link11.com/product-guides/web-ddos/faq/link11-default-values.md).

# Link11 Default Values

Link11 configures a number of default values on our proxies to help mitigate DDoS attacks.

1. `MAX_HTTPHDR_HOST_SIZE`:
   * **Purpose:** Specifies the maximum size allowed for the HTTP Host header in an HTTP request.
   * **Usage:** Used to prevent issues related to excessively large Host headers, such as buffer overflows or denial-of-service attacks.
   * **Value:** 512
2. `MAX_HTTPHDR_USERAGENT_SIZE`:
   * **Purpose:** Sets the maximum size allowed for the HTTP User-Agent header in an HTTP request.
   * **Usage:** Helps control the size of User-Agent information sent by clients, preventing abuse or resource exhaustion.
   * **Value:** 1024
3. `MAX_HTTPHDR_COOKIE_SIZE`:
   * **Purpose:** Defines the maximum size for the HTTP Cookie header in an HTTP request.
   * **Usage:** Controls the size of cookies sent by clients, preventing issues related to excessively large cookies.
   * **Value:** 12288
4. `MAX_HTTPHDR_REFERRER_SIZE`:
   * **Purpose:** Specifies the maximum size allowed for the HTTP Referer (or Referrer) header in an HTTP request.
   * **Usage:** Helps limit the size of referrer information, which is the URL of the previous web page from which a link was followed.
   * **Value:** 4096
5. `MAX_HTTPHDR_RANGE_SIZE`:
   * **Purpose:** Sets the maximum size for the HTTP Range header in an HTTP request.
   * **Usage:** Controls the size of the Range header, which is used for partial content requests (e.g., video streaming).
   * **Value:** 1024