单项选择题
A. /27 B. /28 C. /29 D. /30
Which network mask is the equivalent of 255.255.248.0?（...
单项选择题Which network mask is the equivalent of 255.255.248.0?（）
A. /20 B. /21 C. /22 D. /23
Which two protocols use UDP as a transport protocol by ...
多项选择题Which two protocols use UDP as a transport protocol by default?（）
A. Telnet B. ICMP C. DHCP D. RIP
Which three protocols use UDP as a transport protocol b...
多项选择题Which three protocols use UDP as a transport protocol by default?（）
A. HTTP B. TFTP C. DNS D. SNMP E. SMTP
