Incoming mail for sigma.nn.ru is handled by one mailserver at sigma.nn.ru themselves. sigma.nn.ru has one IP number , which also has a corresponding reverse pointer. solan.ru, admnn.ru, akbnn.ru, pcfko.ru, nipom.ru and at least 64 other hosts point to the same IP. mail.sigma.nn.ru are subdomains to this hostname. nn.ru is a domain controlled by two nameservers at nn.ru themselves. They are on the same IP network. Incoming mail for nn.ru is handled by two mailservers also at nn.ru. Two mailservers have the same IP number. nn.ru has one IP number. sigma.nn.ru is hosted on a server in Russian Federation.