Web-Based Access Control (Wac) - D-Link xStack Reference Manual

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xStack DGS-3200 Series Layer 2 Managed Gigabit Ethernet Switch Web UI Reference Guide
Port List (e.g.: 1, Enter a list of ports.
5-10)
Click the Find button to locate a specific entry based on the information entered. Click the Clear by Port button to clear all the
information linked to the port number entered. Click the View All Hosts button to display all the existing hosts. Click the Clear
All hosts button to clear out all the existing hosts.

Web-based Access Control (WAC)

Web-based Authentication Login is a feature designed to authenticate a user when the user is trying to access the Internet via the
Switch. The authentication process uses the HTTP protocol. The Switch enters the authenticating stage when users attempt to
browse Web pages (e.g., http://www.dlink.com) through a Web browser. When the Switch detects HTTP packets and this port is
un-authenticated, the Switch will launch a pop-up user name and password window to query users. Users are not able to access the
Internet until the authentication process is passed.
The Switch can be the authentication server itself and do the authentication based on a local database, or be a RADIUS client and
perform the authentication process via the RADIUS protocol with a remote RADIUS server. The client user initiates the
authentication process of WAC by attempting to gain Web access.
D-Link's implementation of WAC uses a virtual IP that is exclusively used by the WAC function and is not known by any other
modules of the Switch. In fact, to avoid affecting a Switch's other features, WAC will only use a virtual IP address to
communicate with hosts. Thus, all authentication requests must be sent to a virtual IP address but not to the IP address of the
Switch's physical interface.
Virtual IP works like this, when a host PC communicates with the WAC Switch through a virtual IP, the virtual IP is transformed
into the physical IPIF (IP interface) address of the Switch to make the communication possible. The host PC and other servers' IP
configurations do not depend on the virtual IP of WAC. The virtual IP does not respond to any ICMP packets or ARP requests,
which means it is not allowed to configure a virtual IP on the same subnet as the Switch's IPIF (IP interface) or the same subnet as
the host PCs' subnet.
As all packets to a virtual IP from authenticated and authenticating hosts will be trapped to the Switch's CPU, if the virtual IP is
the same as other servers or PCs, the hosts on the WAC-enabled ports cannot communicate with the server or PC which really
own the IP address. If the hosts need to access the server or PC, the virtual IP cannot be the same as the one of the server or PC. If
a host PC uses a proxy to access the Web, to make the authentication work properly the user of the PC should add the virtual IP to
the exception of the proxy configuration. Whether or not a virtual IP is specified, users can access the WAC pages through the
Switch's system IP. When a virtual IP is not specified, the authenticating Web request will be redirected to the Switch's system IP.
The Switch's implementation of WAC features a user-defined port number that allows the configuration of the TCP port for either
the HTTP or HTTPS protocols. This TCP port for HTTP or HTTPS is used to identify the HTTP or HTTPS packets that will be
trapped to the CPU for authentication processing, or to access the login page. If not specified, the default port number for HTTP is
80 and the default port number for HTTPS is 443. If no protocol is specified, the default protocol is HTTP.
The following diagram illustrates the basic six steps all parties go through in a successful Web Authentication process:
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