Incoming mail for 2a.malkm.com is handled by one mailserver having a total of two IP numbers. They are on different IP networks. coa.ca, qrq.com, koral.com, jesup.net, ner2r.net and at least 100 other hosts share mailservers with this domain. malkm.com is a domain controlled by two nameservers at malkm.com themselves. They are on the same IP network. malkm.com has one IP number.