mx1.siscoit.pl has one IP number , but the reverse is mx1.blink.pl. mx.emef.pl, mx3.arx.pl, mx2.arx.pl, mx1.arx.pl, mx3.blink.pl and at least 87 other hosts point to the same IP. siscoit.pl use this as a mailserver. siscoit.pl is delegated to two nameservers, however both delegated nameservers are missing in the zone and four other nameservers are listed. There are four duplicated IP numbers. Some of them are on the same IP network. Incoming mail for siscoit.pl is handled by two mailservers on different IP networks. siscoit.pl has two IP numbers. They are on the same IP network. mx1.siscoit.pl is hosted on a server in Poland.