Q & A on DNS Architecture Q: Could yould please answer the following questions which I do not know understand with regard to COMPUTER NETWORKS and INTERNETS by Mr Comer 1) Does limiting the number of levels in a DNS hierarchy result in faster name resolution? For example, if an organization limits all names to three segments each instead of allowing say 10 segments, will name resolution be faster? Why or why not? A: There are two issues: topology and computational efficiency. Under topology, lookup is fastest if the organization places all names in a single server. However, for reasons of administration, it may be preferable to have several servers and use the hierarchy to divide names. Under computational efficiency, lookup will slow down if the server is overrun with requests. Thus, if one has a small organization with few simultaneous lookups, a single server works well. Q: With the aid of diagram could you tell me what software is needed on each computer if I want to run a system that has all mailboxes on a single remote computer. A: The single computer that has mailboxes needs: an SMTP server to accept incoming mail a POP3 or IMAP server to allow users to access their mailbox A: Each other computer needs either a POP3 client or an IMAP client to access the mailbox.