A Linux administrator is checking connectivity between two servers in separate subnets:
Server A: 10.1.2.20 (source)
Server B: 10.2.1.10 (destination on port 8080)
The administrator tried to run the curl 10.2.1.10:8080 command on server A and received the following output:
curl: (7) Failed to connect to 10.2.1.10 port 8080: Connection refused.
The administrator checked on server B and confirmed nothing is listening on port 8080.
Which of the following commands, when run on server B, would have allowed the administrator to test the connection successfully?