ns.vuurwerk.nl has one IP number , but the reverse is santpoort.vuurwerk.nl. santpoort.vuurwerk.nl point to the same IP. pz.nl, ja.nl, w8.nl, npv.nl, bga.nl and at least 100 other hosts use this as a nameserver. travelalert.nl use this as a mailserver. vuurwerk.nl is a domain controlled by three nameservers. All of them are on different IP networks. Incoming mail for vuurwerk.nl is handled by five mailservers having a total of three IP numbers. There are six duplicated IP numbers. Some of them are on the same IP network. ns.vuurwerk.nl is hosted on a server in Netherlands.