Attribute Number






Allowed in

Access-Request, Access-Accept

Prohibited in

Access-Reject, Access-Challenge

Presence in Packet

Not required

Maximum Iterations


In link-framed connections using such protocols as SLIP and PPP, the Framed-IP-Address attribute carries, quite obviously, the value of the IP address to be assigned to the connection. Depending on the origin of the Access-Request packet, the attribute has the following different meanings:

From the RADIUS client

The value of this attribute indicates the client’s preference in IP address. The RADIUS server does not have to assign this address, although it may do so.

From the server to the client

The RADIUS server will assign the IP found in this attribute to the connection.

There are exceptions to that rule, however. There are two specific IP values reserved for use by RADIUS. The address is used when the client computer negotiates for the IP it uses—this may be when the user has an assigned static IP address and needs to communicate directly with the IP provisioning equipment in order to get this address. The address is used when the RADIUS client issues the IP address.

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