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