3com 8807 User Guide

C

HAPTER

 27: P

ORTAL

 C

ONFIGURATION

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Portal server is a Web server. Users can access it by using standard WWW 
browsers. The portal server provides free portal service and 
Web-authentication-based interface. The access device exchanges the 
authentication information of the authentication client with the Portal server. 
Internet content provider (ICP) can provide related information about its own 
website to users through this website.

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Authentication/accounting server implements the authentication and 
accounting function for the users. The access device interacts with the 
authentication/accounting server through the RADIUS protocol. 

Portal authentication procedure on 3Com series switches is:

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When the switch receives the login user’s HTTP packets for the first time, it will 
judge whether this user is Portal user at first. For Portal users, the switch allows 
the user to access only the contents of the specified website servers (the Portal 
server and the authentication-free addresses).

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For the HTTP packets of the Portal user to access other websites, the switch will 
redirect them to the Portal server in the way of TCP cheat.

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The Portal server provides a Web interface for users to input usernames and 
passwords. The input usernames and passwords are forwarded to the switch 
through the Portal server.

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The switch sends the usernames and passwords to the authentication server 
for authentication. The switch allows a user to access Internet only after he 
passes the authentication, and then the switch will not redirect HTTP packets of 
this user.

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In 3Com series switches, Portal runs in one of the following three methods: Direct 
authentication method, ReDHCP authentication method and Layer 3 
authentication method.

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Direct authentication method: In this method, the user gets a public address 
directly. Before passing authentication, the user can access only the Portal 
server and the set authentication-free addresses. The user can access Internet 
after passing authentication.

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ReDHCP authentication method: In this method, the user gets a private address 
through DHCP before passing authentication. Before passing authentication, 
the user can access only the Portal server and the set authentication-free 
addresses. The user can apply for a public address and access Internet after 
passing authentication.

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Layer 3 Portal authentication method: This method expands the Direct 
authentication method. In this method, the user can access the Portal-enabled 
switch across network segments.

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Considering security problems, both the Direct authentication method and the 
ReDHCP authentication method require checking MAC addresses of the user. 
So Portal can be enabled only on the first Layer 3 interface that the user