A traffic analysis on the domain name system (DNS) server of Kumamoto University was carried out with the multivariate statistical analysis. It is found that the total number of DNS packets, Dq , are generated from an electronic mail (E-mail) server, as represented: Dq = mSMTP NSMTP + mPOP3 NPOP3 , where NSMTP and NPOP3 represent the number of the simple mail transfer protocol (SMTP) access and that of the post office protocol version 3 (POP3) access, respectively. The linear coefficients mSMTP and mPOP3 are calculated to be 8.6 and 1.0. From these results, it is clearly concluded that the DNS access from the E-mail server is mainly driven by the SMTP access to a greater extent than the POP3 access. Also, it is found that mSMTP is represented, as follows: mSMTP = 2+4n(1-q), where q is a mail-receiving rate and n is a number of different domain hosts.