ContextId parameter specifies how to derive a lookup key for TACACS+ authentication context when authorizing TACACS+ requests. Context specific special characters supported are: TACACS+ client IP address (%0), TACACS+ client source TCP port (%1), TACACS+ user (%2), TACACS+ port (%3), TACACS+ rem_addr (%4). The default is fine for the most cases. Defaults to %2:%0.

# Base context lookup only on username
ContextId %2