Samuel boa tarde.
Na Versão 11.5.6 do DB2 ele usa a porta 25000 kkkk

Database application uses this port when it connects to the database server.
If on Db2 Version 11.5.5 and older, the default port number is 50000.
If on Db2 Version 11.5.6 and newer, the default port number is 25000.