lab.cs.swarthmore.edu is an alias that includes about 10 machines from the lab. You can ssh to lab.cs.swarthmore.edu and you will get one of those 10 machines.
$ host lab.cs.swarthmore.edu lab.cs.swarthmore.edu has address 130.58.68.150 lab.cs.swarthmore.edu has address 130.58.68.152 lab.cs.swarthmore.edu has address 130.58.68.153 lab.cs.swarthmore.edu has address 130.58.68.158 lab.cs.swarthmore.edu has address 130.58.68.159 lab.cs.swarthmore.edu has address 130.58.68.162 ... SPINACH[~]$ host 130.58.68.150 150.68.58.130.in-addr.arpa domain name pointer lavender.cs.swarthmore.edu