# SNMP Traps and System Log Messages Overview

The router can send Simple Network Management Protocol (SNMP) traps to alert network managers when:

- A RADIUS server fails to respond to a request.
- A RADIUS server that previously failed to respond to a request (and was consequently removed from the list of active servers) returns to active service.

  Returning to active service means that the E Series RADIUS client receives a valid response to an outstanding RADIUS request after the server is marked unavailable.

- All RADIUS servers within a VR context fail to respond to a request.

The router also generates system log messages when RADIUS servers fail to respond or when they return to active service; no configuration is required for system log messages.

- SNMP Traps
- System Log Messages

## SNMP Traps

The router generates SNMP traps and system log messages as follows:

- If the first RADIUS server fails to respond to the RADIUS request, the E Series RADIUS client issues a system log message and, if configured, an SNMP trap indicating that the RADIUS server timed out. The E Series RADIUS client will not issue another system log message or SNMP trap regarding this RADIUS server until the deadtime expires, if configured, or for 3 minutes if deadtime is not configured.
- The E Series RADIUS client then sends the RADIUS request to the second configured RADIUS server. If the second RADIUS server fails to respond to the RADIUS request, the E Series RADIUS client again issues a system log message and, if configured, an SNMP trap indicating that the RADIUS server timed out.
- This process continues until either the E Series RADIUS client receives a valid response from a RADIUS server or the list of configured RADIUS servers is exhausted. If the list of RADIUS servers is exhausted, the E Series RADIUS client issues a system log message and, if configured, an SNMP trap indicating that all RADIUS servers have timed out.

If the E Series RADIUS client receives a RADIUS response from a “dead” RADIUS server during the deadtime period, the RADIUS server is restored to active status.

If the router receives a valid RADIUS response to an outstanding RADIUS request, the E Series client issues a system log message and, if configured, an SNMP trap indicating that the RADIUS server is now available.

## System Log Messages

You do not need to configure system log messages. The router automatically sends them when individual servers do not respond to RADIUS requests and when all servers on a VR fail to respond to requests. The following are the formats of the warning level system log messages:

RADIUS [ authentication | accounting ] server serverAddress unavailable in VR virtualRouterName [; trying nextServerAddress]RADIUS no [ authentication | accounting ] servers responding in VR virtualRouterName RADIUS [ authentication | accounting ] server serverAddress available in VR virtualRouterName