It's not 'used' as in 'the system is desperately out of RAM and turfing things onto disk to make room', but 'used' as in 'we have 5 gigabytes of swap reserved to match currently allocated memory'. ...
depends on what is in the hostname.X file... usually you'll find a "hostname" and this "hostname" should be in the /etc/hosts file where he goes and read the ip...