Incoming mail for us.ibm.com is handled by 18 mailservers. Some of them are on the same IP network. ibm.com, ca.ibm.com, jp.ibm.com, mx1.ibm.com, buildforge.com and at least five other hosts share mailservers with this domain. nc.us.ibm.com, ct.us.ibm.com, co.us.ibm.com, ny.us.ibm.com, dns.us.ibm.com and at least ten other hosts are subdomains to this hostname. ibm.com is a domain controlled by four nameservers. All of them are on different IP networks. Incoming mail for ibm.com is handled by eleven mailservers. Some of them are on the same IP network. ibm.com has three IP numbers. All of them are on different IP networks.