A DRDA host database resides on a z/OS or an i5/OS and listens on port 446. The TCP/IP address for this system is 192.168.10.1 and the TCP/IP host name is myhost. Which of the following commands is required to update the local node directory so that a DB2 client can access this DRDA database?

The CATALOG TCPIP NODE command requires: a local node name (what you're naming it locally), the remote hostname, and the port. Option B is correct: 'mydb2srv' is the local node name, 'myhost' is the remote hostname, and 446 is the port. Options A and C use 'myhost' as the node name (incorrect), and D uses an IP address instead of hostname for the SERVER parameter (should be port number).