irq.org, fmbb.net, jps2.net, haux.com, cetaf.org and at least 100 other hosts use this as a nameserver. one.com is a domain controlled by two nameservers at b-one-dns.net. They are on the same IP network. Incoming mail for one.com is handled by two mailservers at one.com themselves. They are on the same IP network. one.com has one IP number.