Accounting-Request |
Packet Type | Request |
Code | 4 |
Identifier | Unique for each request; unique for each transmission of modified data |
Authenticator | Request |
Attribute Data | 0 or more attributes |
Accounting-Request packets are sent from the client to the server. Remember that a client can be a true RADIUS client or another RADIUS server acting as a proxy. The client sends the packet with the code field set to 4 . When the server receives this request packet, it is required to transmit an acknowledgment to the client unless it cannot handle or process the packet. In this case, it cannot transmit anything to the client.
With the exceptions of the User -Password , CHAP-Password , Reply-Message , and State attributes, any other attribute allowed in an Access-Request or Access-Accept packet can be used inside an Accounting-Request packet.
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There are a couple more caveats to presence in the packet. As mentioned in Chapter 2, the NAS-IP-Address and NAS-Identifier attributes are mutually exclusive, meaning that one or the other must be included in a packet, but not both. The RFC recommends distinguishing the NAS port or type of port in the packet by using the NAS-Port or NAS-Port-Type attributes unless that information is superfluous to the service. Additionally, the Framed-IP-Address must include the real IP address of the user.
Accounting-Response |
Packet Type | Response |
Code | 5 |
Identifier | Identical to corresponding Accounting-Request |
Authenticator | Response |
Attribute Data | 0 or more attributes |
The Accounting-Response packets are primarily designed as acknowledgment packets to be sent from the accounting server to the client, indicating that the request from the client has been received and logged. If the packet was indeed processed and logged successfully, the RFC mandates that the code field of the acknowledgment section be set to 5 to indicate a response. Since the identifier of the response packet is identical to the corresponding Accounting-Request field, the client can easily match the two packets together to keep track of which requests have been fulfilled and which are outstanding.
Not only do Accounting-Response packets not have to contain any attributes, but in practice it is rare for them to do so. However, in the case of a proxy transaction, the Proxy-State attribute can be included in the packet. As well, any vendor-specific attributes may be included in Accounting-Response packets .