Dell N3200-ON Networking N-Series Switches User Guide version 6.8.0 - Page 351

Captive Portal and DNS CP allows unauthenticated users access to DNS services on TCP and UDP destination port 53. CP inspects all DNS traffic to ensure that it conforms with the DNS protocol (RFC 1035/1996). CP checks the format of DNS messages and discards packets that do not conform to the minimum standards. Specifically, CP performs the following checks on a DNS packet: • The packet must have a full-size header and at least one question field • The packet must have a valid DNS response code • The first question field must not exceed 63 octets in length, nor must the length field be greater than 63 • The first question class field must be valid. Captive Portal Troubleshooting The following table explains the status values for CP authentication sessions and the resulting actions taken, if any. CP global status, interface status, and session status are available in the user interfaces. Table 9-13. Captive Portal Status Values Status Value Default Serve Validate WIP Description Browser Action Initial request from the client. Used to detect initial request. Default serve. Used when serving the initial connection page. Actual validation request. Indicates that the user has submitted credentials and requests authentication. Indicates that validation is in progress. The validation page begins to poll the server until the status flag changes. The actual poll request is the same http(s) request used to "validate" as described above. While waiting between polls, the browser displays an "authorization in process" message. Authentication, Authorization, and Accounting 351