Internet-Security.com TCP port 448 details

TCP/448 is the IANA-registered ddm-ssl service: IBM Distributed Data Management over SSL/TLS.
It is used on IBM i (AS/400, iSeries/System i) to provide secure DRDA/DDM access to the DB2 for i database and other DDM functions.
Real examples: IBM i Access Client Solutions (ACS) and IBM Data Server Driver/DB2 Connect clients connect to DB2 for i over DRDA with TLS using port 448 on the server.
IBM Toolbox for Java (JTOpen)–based applications and IBM i remote services (secure remote file transfer, spool/printer access, and Remote Command) also use 448 when SSL is enabled for DDM.
Outside the IBM i ecosystem, TCP/448 has little to no common use.

TCP 448