Name
Callback-Number
Synopsis
Attribute Number |
19 |
Length |
3 or more octets |
Value |
STRING |
Allowed in |
Access-Request, Access-Accept |
Prohibited in |
Access-Reject, Access-Challenge |
Presence in Packet |
Not required |
Maximum Iterations |
1 |
The value of this attribute is the
number to which the RADIUS client gear should return a call to the
authenticating user. Depending on what packet this attribute is found
in, different actions may be configured. For instance, if
Callback-Number
is found in an
Access-Request
packet, the implementation may
assume that the end user is requesting callback service. If the
attribute is found in the Access-Accept
packet, it
can mean anything that the administrator configuring the gear wants
it to mean. In fact, in some cases, Callback-ID
and Callback-Number
will not
be found together in one packet.
Coupled with the Callback-ID
attribute, this
attribute is one of several RADIUS security measures. In addition to
being more convenient and cost-effective for companies with employees
in hotels needing access to corporate IT resources, the callback
mechanism is also a security device. The implementation could be
configured to call a certain number when a certain username requests
access. This way, if a hacker is located somewhere other than where
the genuine user normally connects from, the
hacker would not be
able to authenticate.
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