Cisco 7604 Configuration Guide - Page 477

Chapter 22 Applying Application Layer Protocol Inspection HTTP Inspection To create an HTTP inspection policy map, perform the following steps: Step 1 Step 2 Step 3 (Optional) Add one or more regular expressions for use in traffic matching commands according to the "Creating a Regular Expression" section on page 20-11. See the types of text you can match in the match commands described in Step 3. (Optional) Create one or more regular expression class maps to group regular expressions according to the "Creating a Regular Expression Class Map" section on page 20-14. (Optional) Create an HTTP inspection class map by performing the following steps. A class map groups multiple traffic matches. Traffic must match all of the match commands to match the class map. You can alternatively identify match commands directly in the policy map. The difference between creating a class map and defining the traffic match directly in the inspection policy map is that the class map lets you create more complex match criteria, and you can reuse class maps. To specify traffic that should not match the class map, use the match not command. For example, if the match not command specifies the string "example.com," then any traffic that includes "example.com" does not match the class map. For the traffic that you identify in this class map, you can specify actions such as drop, drop-connection, reset, mask, set the rate limit, and/or log the connection in the inspection policy map. If you want to perform different actions for each match command, you should identify the traffic directly in the policy map. a. Create the class map by entering the following command: hostname(config)# class-map type inspect http [match-all | match-any] class_map_name hostname(config-cmap)# Where class_map_name is the name of the class map. The match-all keyword is the default, and specifies that traffic must match all criteria to match the class map. The match-any keyword specifies that the traffic matches the class map if it matches at least one of the criteria. The CLI enters class-map configuration mode, where you can enter one or more match commands. b. (Optional) To add a description to the class map, enter the following command: hostname(config-cmap)# description string c. (Optional) To match traffic with a content-type field in the HTTP response that does not match the accept field in the corresponding HTTP request message, enter the following command: hostname(config-cmap)# match [not] req-resp content-type mismatch d. (Optional) To match text found in the HTTP request message arguments, enter the following command: hostname(config-cmap)# match [not] request args regex [regex_name | class regex_class_name] Where the regex_name is the regular expression you created in Step 1. The class regex_class_name is the regular expression class map you created in Step 2. e. (Optional) To match text found in the HTTP request message body or to match traffic that exceeds the maximum HTTP request message body length, enter the following command: hostname(config-cmap)# match [not] request body {regex [regex_name | class regex_class_name] | length gt max_bytes} Where the regex regex_name argument is the regular expression you created in Step 1. The class regex_class_name is the regular expression class map you created in Step 2. The length gt max_bytes is the maximum message body length in bytes. OL-20748-01 Catalyst 6500 Series Switch and Cisco 7600 Series Router Firewall Services Module Configuration Guide using ASDM 22-61