We pick c.root-servers.net, one of the 13 root servers (1), and ask it about webmail.umuc.edu and learn that edu is delegated to six name servers (2), so we ask a.edu-servers.net where we learn that umuc.edu is delegated to four name servers, including ns1.umuc.edu (3), so we ask that one and get the following answer:
Incoming mail for webmail.umuc.edu is handled by two mail servers at umuc.edu. Both are on the same IP network. Webmail.umuc.edu has one IP number (131.171.9.99), which also has a corresponding reverse pointer.