Supported fields and operators

The fields that are supported by load balancing rules depend on whether Cloudflare proxies the traffic going through your load balancer or not.

If you use the wrong set of fields, you might see unexpected behaviors. For best results, use the fields associated with your traffic’s proxy status.

Also, some Load Balancing rules fields are available on the Expression Builder - as described in Load Balancing expressions - while others can only be configured manually, via API or Expression Editor

Expression Builder field sets

Consider the following table to know how the fields available in the Expression Builder are grouped.

Field Set	Section in Expression Builder	Description
Fields supported regardless of proxy	BOTH	Values that are always accessible regardless of the load balancer proxy status.
Proxied-only fields	PROXIED ONLY	Values accessible only when the load balancer is proxied.
Unproxied-only fields	NON-PROXIED ONLY	Values accessible only when the load balancer is not proxied (DNS-only traffic).

Fields supported regardless of proxy

Regardless of your traffic proxy status, Load Balancing rules can access values for the following fields:

Field	Name in Expression Builder	Description
cf.load_balancer.name Bytes	Load Balancer Name	Represents the name of the load balancer executing these rules. Example value: lb.example.com
cf.load_balancer.region Bytes	Load Balancer Region	Provides the region name of the data center processing the request. Example value: ENAM
ip.src IP address	IP Source Address	If proxied, this field provides the client TCP IP address, which may be adjusted to reflect the actual address of the client by using HTTP headers such as X-Forwarded-For or X-Real-IP. If unproxied (DNS-only), this field provides the ECS source address, if available. If not available, it provides the client resolver IP address. Deprecation Warning: In the future, this field will always be set to the client resolver IP address for unproxied requests. To check for the presence of ECS and use the ECS IP, see the fields dns.rr.opt.client and dns.rr.opt.client.addr, respectively. Example value: 1.2.3.4

Proxied-only fields

If your traffic is proxied through Cloudflare, you have access to all the fields listed under Fields supported regardless of proxy in addition to the following fields:

Many of these fields are referenced from the Rules language documentation.

Field	Name in Expression Builder	Description
http.cookie String	(Manual entry only)	Represents the entire cookie as a string. Example value: session=8521F670545D7865F79C3D7BEDC29CCE;-background=light
http.host String	(Manual entry only)	Represents the hostname used in the full request URI. Example value: www.example.org ↗
http.referer String	(Manual entry only)	Represents the HTTP Referer request header, which contains the address of the web page that linked to the currently requested page. Example value: Referer: htt­ps://developer.example.org/en-US/docs/Web/JavaScript
http.request.headers Map<Array<String>>	Header	Represents HTTP request headers as a Map (or associative array). The keys of the associative array are the names of HTTP request headers converted to lowercase. When there are repeating headers, the array includes them in the order they appear in the request. Decoding: no decoding performed Whitespace: preserved Non-ASCII: preserved Example: any(http.request.headers[“content-type”][*] == “application/json”) Example value: {"content-type": ["application/json"]}
http.request.method String	Request Method	Represents the HTTP method, returned as a string of uppercase characters. Example value: GET
http.request.timestamp.sec Integer	Timestamp	Represents the timestamp when Cloudflare received the request, expressed as Unix time in seconds. This value is 10 digits long. Example value: 1484063137
http.request.uri String	URI	Represents the URI path and query string of the request. Example value: /articles/index?section=539061&expand=comments
http.request.uri.args Map<Array<String>>	(Manual entry only)	Represents the HTTP URI arguments associated with a request as a Map (associative array). When an argument repeats, then the array contains multiple items in the order they appear in the request. The values are not pre-processed and retain the original case used in the request. Decoding: no decoding performed Non-ASCII: preserved Example: any(http.request.uri.args[“search”][*] == “red+apples”) Example value: {"search": ["red+apples"]}
http.request.uri.args.names Array<String>	(Manual entry only)	Represents the names of the arguments in the HTTP URI query string. The names are not pre-processed and retain the original case used in the request. When a name repeats, the array contains multiple items in the order that they appear in the request. Decoding: no decoding performed Non-ASCII: preserved Example: any(http.request.uri.args.names[*] == “search”) Example value: [“search”]
http.request.uri.args.values Array<String>	(Manual entry only)	Represents the values of arguments in the HTTP URI query string. The values are not pre-processed and retain the original case used in the request. They are in the same order as in the request. Duplicated values are listed multiple times. Decoding: no decoding performed Non-ASCII: preserved Example: any(http.request.uri.args.values[*] == “red+apples”) Example value: [“red+apples”]
http.request.uri.path String	URI Path	Represents the URI path of the request. Example value: /articles/index
http.request.uri.query String	URI Query	Represents the entire query string, without the ? delimiter. Example value: section=539061&expand=comments
http.request.version String	HTTP Version	Represents the version of the HTTP protocol used. Use this field when you require different checks for different versions. Example Values: HTTP/1.1 HTTP/3

Unproxied-only fields

If your traffic is not proxied through Cloudflare, you have access to all the fields listed under Fields supported regardless of proxy in addition to the following fields:

Field	Name in Expression Builder	Description
dns.qry.name Bytes	Query Name	Represents the query name asked. Example value: example.com.
dns.qry.name.len Integer	Query Name Length	Represents the length in bytes of the query name. Example value: 123
dns.qry.qu Boolean	Question	When true, this field indicates that the received DNS message was a question.
dns.qry.type Integer	Query Type	Represents the numeric value of the DNS query type. Example Values: 1 (A record) 28 (AAAA record)
dns.rr.opt.client Boolean	(Manual entry only)	When true, this field indicates that the EDNS Client Subnet (ECS) address was sent with the DNS request.
dns.rr.opt.client.addr String	(Manual entry only)	If present, this field represents the ECS address sent with the DNS request. Example value: 1.2.3.0

Operators and grouping symbols

• Comparison operators specify how values defined in an expression must relate to the actual HTTP request value for the expression to return true.

• Logical operators combine two expressions to form a compound expression and use order of precedence to determine how an expression is evaluated.

• Grouping symbols allow you to organize expressions, enforce operator precedence, and nest expressions.

For examples and usage, refer to Operators and grouping symbols in the Rules language documentation.