i have a 3550 with ipservices 12.2(44) upgraded from c3550-i5q3l2-mz.121-22.EA4.bin when the reload is completed, the switch is no longer authenticating to tacacs and failing back to the local user and password
Did you define source interface for tacacs authentication.
On router issue command,
ip tacacs source-interface fastethernet x/y , where interface would be the one mentioned in tacacs server.
That should fix it.
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