SymmetricDS Setup - SQL Server 2008 to MySQL
It seem that the official documents are not clear enough to help you.
The steps are below:

You need 1( or 2) intermediate node(s)(Linux or Windows) which have connection between Source and Destination databases and install symmetricDs on it.

You need to build the schema(database structure) on the destination(Mysql) node by symmetricds script or by insert yourself.

You need to create 2 users on 2 nodes who have access at read and write to database

You need to create the engine file for source and destination in the intermediate(s) node similar like this:


For mssql.properties
  engine.name=MSSQL
  db.driver=net.sourceforge.jtds.jdbc.Driver
db.url=jdbc:jtds:sqlserver://[sqlserver:port]/[DatabaseName];useCursors=true;bufferMaxMemory=10240;lobBuffer=5242880

 db.user=[username]
 db.password=[password]

registration.url=
sync.url=http://localhost:8080/sync/MSSQL

group.id=source
external.id=0000000


job.purge.period.time.ms=7200000


job.routing.period.time.ms=5000

 job.push.period.time.ms=10000

 job.pull.period.time.ms=10000

 initial.load.create.first=true

For mysql.properties
engine.name=mysql

db.driver=com.mysql.jdbc.Driver

db.url=jdbc:mysql://&lt;IP&gt;/databasename?tinyInt1isBit=false


registration.url=http://localhost:8080/sync/MSSQL


group.id=destination
external.id=0000002

job.routing.period.time.ms=5000

job.push.period.time.ms=10000

job.pull.period.time.ms=10000

jobs.synchronized.enable=true


On  the intermediate  Node, You will need to CREATE SYMMETRICDS CONFIGURATION TABLES with following bin\symadmin --engine source create-sym-tables
On  the intermediate  Node, You need  sql file containing the initial table configurations to insert to source engine node with at least 4 parameter below to make trigger and synchronization:

insert into sym_node_group (node_group_id, description) values ('MSSQL', 'SQL Servers Group');

insert into sym_node_group (node_group_id, description) values ('MYSQL', 'MYSQL server');

insert into sym_node_group_link (source_node_group_id, target_node_group_id, data_event_action) values ('MSSQL', 'MYSQL', 'P');

insert into sym_router 
(router_id,source_node_group_id,target_node_group_id,router_type,create_time,last_update_time)
values('MSSQL_2_MYSQL', 'MSSQL', 'MYSQL', 'default',current_timestamp, current_timestamp);
    
insert into sym_channel (channel_id, processing_order, max_batch_size, enabled, description) values ('main_channel', 1, 100000, 1, 'channel for replication');
 
insert into sym_trigger (trigger_id,source_table_name,channel_id,last_update_time,create_time) values ('table1','table1','main_channel',current_timestamp,current_timestamp);
    
insert into sym_trigger_router (trigger_id,router_id,initial_load_order,last_update_time,create_time) values ('table1','MSSQL_2_MYSQL', 100, current_timestamp, current_timestamp);

insert into sym_trigger (trigger_id,source_table_name,channel_id,last_update_time,create_time) values ('table2','table2','main_channel',current_timestamp,current_timestamp);
    
insert into sym_trigger_router (trigger_id,router_id,initial_load_order,last_update_time,create_time) values ('table2','MSSQL_2_MYSQL', 100, current_timestamp, current_timestamp);


And the last step is run the script for source engine node and destination engine node.
If you want the connection is only one-way just