Snooping RADIUS Accounting Requests for IP-Based Subscribers Overview
When the gateway GPRS support node (GGSN), Packet Data Network Gateway (PGW), or broadband network gateway (BNG) does not identify a router as a RADIUS server, RADIUS accounting requests are not sent to the router IP address and interface configured for RADIUS messages. In this situation, you can configure the router to actively examine RADIUS accounting requests that pass through the router. This process is known as snooping. Junos OS identifies accounting requests that match a filter you configure, copies those requests, and sends them to the subscriber processing module.
To configure snooping, you configure filters called snoop segments. You can include the following conditions in a snoop segment:
Destination IP address of the accounting request
Shared secret between the accounting request sender and the router
(Optional) Destination port of the accounting request
(Optional) Router interface that receives the accounting request
(Optional) Source IP address of accounting requests from a GGSN, PGW, or BNG
You can also configure the length of time to cache the accounting request that was snooped. Any duplicate request that is received by the router within this time is dropped.
You can configure multiple snoop segments.