nsauth2.introweb.nl has one IP number , which also has a corresponding reverse pointer. cnt.nl, cph.nl, tvz.nl, sko.nl, tsd.nl and at least 100 other hosts use this as a nameserver. introweb.nl is a domain controlled by three nameservers. All of them are on different IP networks. Incoming mail for introweb.nl is handled by one mailserver at introweb.nl themselves. introweb.nl has one IP number. nsauth2.introweb.nl is hosted on a server in Netherlands.