RADIUS accounting with IP attribute

The RADIUS Attribute 8 (Framed-IP-Address) feature provides the RADIUS server with information about the client’s IP address after the client is authenticated. DHCP snooping is queried for the IP address of the client, so DHCP snooping must be enabled for the VLAN of which the client is a member.

When the switch begins communications with the RADIUS server it sends the IP address of the client requesting access to the RADIUS server as RADIUS Attribute 8 (Framed-IP-Address) in the RADIUS accounting request. The RADIUS server can use this information to build a map of user names and addresses.

It may take a minute or longer for the switch to learn the IP address and then send the accounting packet with the Framed-IP-Address attribute to the RADIUS server. If the switch does not learn the IP address after a minute, it sends the accounting request packet to the RADIUS server without the Framed-IP-Address attribute. If the IP address is learned at a later time, it is included in the next accounting request packet sent.

The switch forwards the accounting information it collects to the designated RADIUS server, where the information is formatted, stored, and managed by the server. For more information on this aspect of RADIUS accounting, see the documentation provided with your RADIUS server.