Access to a database from a Spark job in synapse

I'm working within a Synapse workspace. I have a linked service to a oracle database in a private network (10.x.x.x) I have a SparkJob which is trying to connect to that database with the oracle thin client and the default method in the spark library, i.e. spark.read.jdbc, and it can not reach it. Is it possible for the spark job to reach the database? I've tried to open firewall connections but can not find from where to where because the Spark pool is in a virtual network for which I don't know the network segment.