Which of the following seivices use UDP? (Choose three.)
A.
Telnet
B.
TFTP
C.
SNMP
D.
DNS
E.
SMTP
F.
HTTP
Explanation:
Common TCP/UDP ports:
TCP ports:
FTP data
FTP control
23 Telnet
25 SMTP
53 DNS
80 WWW
100 POP3
UDP ports:
53 DNS
69 TFTP
161 SNMP
Note: DNS use TCP for regional transmission, and use UDP for name inquiry.