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Auto Mode automatically tries to find out which proxy can be used. For this purpose the IP route into the IPMI network is checked on each proxy. The first proxy that has a suitable IP route is used as a proxy. If a different subnet is used for each IPMI network, it should be sufficient to enable only this option without further assignment of ACL groups or NOC-PS servers. However, if you know exactly which proxy should be used under which circumstances, it is better to create a fixed assignment for performance reasons. Depending on the number of proxies, it can take a few seconds for the module to find the right proxy in auto mode.
Verify proxy election
Please see following article to test the proxy election: Test proxy election