Exim Configuration Manager -> Advanced Editor

log_selector:

+incoming_port +smtp_connection +all_parents +retry_defer +subject +arguments +received_recipients +address_rewrite +arguments +connection_reject +delay_delivery +delivery_size +dnslist_defer +incoming_interface +lost_incoming_connection +queue_run +received_sender +sender_on_delivery +size_reject +skip_delivery +smtp_confirmation +smtp_protocol_error +smtp_syntax_error +tls_cipher +tls_peerdn