3Com 10014299 Configure User with Caller Number, Configure FTP User and the Usable Directory

538CHAPTER 38: CONFIGURING AAA AND RADIUS PROTOCOL

The Callback technique enhances security. In the processing of a Callback, the server calls the client according to the call number configured locally. This avoids security risks caused by leakage of user name or password. The server can also classify call-in requests according to its configuration as refuse call, accept call (no call back) or accept callback. This serves to exert different limitations upon different clients and take initiative in ensuring resource access when there are incoming calls.

The callback technique has the following advantages:

■Saves communication expenses, especially when the call charge rates of two directions are different)

■Changes the call charge bearer

■Combines call charge lists

The security devices in 3Com routers support the callback technique that is divided into ISDN caller authentication callback and callback participated in by PPP.

ISDN caller authentication callback does not involve PPP, it directly authenticates whether the call-in number matches with the number configured by the server. Hence, only the server end needs a corresponding configuration and the client needs no modification.

Table 607 Configure Callback User and the Callback Number

Operation	Command
Configure the callback user and the	local-user user [ callback-number
callback number	number ] ...
Delete the callback user and the callback	undo local-user user
number

A RADIUS server can be configured with callback-number,equivalent to number, which is defined locally. If aaa authentication-scheme ppp default radius is configured then number, which is configured locally, is invalid and the number to be transmitted to PPP will be decided by callback-numberset on RADIUS server. If aaa authentication-scheme ppp default radius local is configured, local authentication is used only when the RADIUS server does not respond, and here number defined locally can work. If aaa authentication-scheme ppp default none is configured, number defined locally does not work.

Configure User with Caller Number

After users with caller numbers are configured, the call-in caller numbers of users calling in can be authenticated in order. At present, only ISDN users can be configured to be such type of users.

Table 608 Configure User with Caller Number

Operation	Command
Configure a user with caller number	local-user user [ call-number number
	] [ :sub-number ] ...
Delete a user with caller number	undo local-user user-name

Configure FTP User and the Usable Directory

An FTP user and the FTP directory available for the user can be configured in the local database. The function is reserved temporarily for future extension.