Examples of rate-based policies
This topic lists some examples of rate-based policies.
Limit the number of requests from a URL
Run the following commands to limit the number of requests per second from a URL:
add stream selector ipStreamSelector http.req.url "client.ip.src"
add ns limitIdentifier ipLimitIdentifier -threshold 4 -timeSlice 1000 -mode request_rate -limitType smooth -selectorName ipStreamSelector
add responder action myWebSiteRedirectAction redirect "\"http: //www.mycompany .com/\""
add responder policy ipLimitResponderPolicy "http.req-url.contains(\"myasp.asp\") && sys.check_limit(\"ipLimitIdentifier\")" myWebSiteRedirectaction
bind responder global ipLimitResponderPolicy 100 END -type default
Cache a response for the request URL
Run the following commands to cache a response if the request URL rate is more than 5 per 20000 milliseconds:
add stream selector cacheStreamSelector http.req.url
add ns limitidentifier cacheRateLimitIdentifier -threshold 5 -timeSlice 2000 -selectorName cacheStreamSelector
add cache policy cacheRateLimitPolicy -rule "http req.method.eq(get) && sys.check_limit \"cacheRateLimitIdentifier\")" -action cache
bind cache global cacheRateLimitPolicy -priority 10
Drop a connection based on cookies
Run the following commands to drop a connection based on the cookies when the following conditions are met:
-
cookies are received in requests from
www.mycompany.com -
the number of requests are more than the rate limit
add stream selector reqCookieStreamSelector "http req.cookie «value(\"mycookie\")" "client.ip.src.subnet(24)"
add ns limitIdentifier myLimitIdentifier -Threshold 2 -timeSlice 3000 -selectorName reqCookieStreamSelector
add responder action sendRedirectUrl redirect '\"http://www.mycompany.com\" + http.req.url' -bypassSafetyCheck YES
add responder policy rateLimitCookiePolicy "http. req.url.contains(\"www.yourcompany.com\") && sys check_limit(\"myLimitIdentifier\")" sendRedirectUrl
Drop a DNS packet from a particular IP address
Run the following commands to drop a DNS packet if the requests from a particular client IP address and DNS domain are more than the rate limit:
add stream selector dropDNSStreamSelector client udp.dns.domain client.ip.src
add ns limitIdentifier dropDNSRateIdentifier -timeslice 20000 -mode request_rate -selectorName dropDNSStreamSelector -maxBandwidth 1 -trapsintimeslice 20
add dns policy dnsDropOnClientRatePolicy "sys check_limit (\"dropDNSRateIdentifier\")" -drop yes
Limit the number of HTTP requests from the same host
Run the following commands to restrict the number of HTTP requests that:
-
Originate from the same host
-
Use a subnet mask of 32
-
Are directed to the same destination IP address
add stream selector ipv6_sel CLIENT.IPv6.SRC.SUBNET(32) CLIENT.IPv6.DST HTTP.REQ.URL
add ns limitIdentifier ipv6_id -timeSlice 20000 -selectorName ipv6_sel
add lb vserver ipv6_vip HTTP 3ffe::209 80 -persistenceType NONE -cltTimeout 180
add responder action redirect_page redirect "\"http://redirectpage.com/\""
add responder policy ipv6_resp_pol "SYS.CHECK_LIMIT(\"ipv6_id\")" redirect_page
bind responder global ipv6_resp_pol 5 END -type DEFAULT