Incoming mail for cl.sdsc.edu is handled by one mailserver at sdsc.edu. cl.sdsc.edu has one IP number , which also has a corresponding reverse pointer. rcsb.org, sdsc.edu, dev.afcs.org, cvs.sdsc.edu, ns1.sdsc.edu and at least 100 other hosts share mailservers with this domain. sdsc.edu is a domain controlled by four nameservers. All of them are on different IP networks. Incoming mail for sdsc.edu is handled by one mailserver also at sdsc.edu. cl.sdsc.edu is hosted on a server in United States.