Sure, create a app relay connector on the Exch Server and scope to the IP address of that Linux Server
https://practical365.com/exchange-2016-smtp-relay-connector/?sfw=pass1617217754
https://learn.microsoft.com/en-us/exchange/mail-flow/connectors/allow-anonymous-relay?view=exchserver-2019#step-1-create-a-dedicated-receive-connector-for-anonymous-relay