多项选择题
Choose the most correct statements about SMTP/ESMTP. （）
A. Open mail relays are often used for spamming. B. ESMTP does NOT provide more security features than SMTP C. SMTPdoes provide authenticated email sending." D. Worms often spread via SMTP.
单项选择题 CiscoCleanAccessensuresthatcomputersconnectingtoyournetworkhavewhichofthefollowing？（）
单项选择题 Whichoftheseisthebestwaytoprovidesendernon-repudiation？（）
单项选择题 WhatgroupinCiscoIOSdoes1536-bitDiffie-Hellmanprimemodulusequivalenttoo？（）
