CMS专题
单选题Which protocol below uses TCP port 443?（）A HTMLB HTTPSC TFTPD TelnetE SMTP
题目
HTML
HTTPS
TFTP
Telnet
SMTP
相似问题和答案
第1题：
A. SIP (port 626)
B. TCP (port 646)
C. UDP (port 606)
D. IP (protocol code LDP)
第2题：
Which protocol and port have been assigned by IANA for RADIUS authentication？（）
- A、UDP/1812
- B、UDP/1813
- C、TCP/1812
- D、TCP/1813
正确答案:A
第3题：
Regarding DHCP (dynamic host configuration protocol), which two of the following choices below are true? (Select two answer choices)
A. The DHCP Discover message uses FF-FF-FF-FF-FF as the Layer 2 destination address.
B. The DHCP Discover message uses UDP as the transport layer protocol.
C. The DHCP Discover message uses a special Layer 2 multicast address as the destination address.
D. The DHCP Discover message uses TCP as the transport layer protocol.
E. The DHCP Discover message does not use a Layer 2 destination address.
F. The DHCP Discover message does not require a transport layer protocol.
A,B 解析：Explanation:
DHCP uses UDP as its transport protocol. DHCP messages from a client to a server are sent to the DHCP server port (UDP port 67), and DHCP messages from a server to a client are sent to the DHCP client port (UDP port 68).The client broadcasts a DHCPDISCOVER message on its local physical subnet. The DHCPDISCOVER message may include options that suggest values for the network address and lease duration. BOOTP relay agents may pass the message on to DHCP servers not on the same physical subnet.
Each server may respond with a DHCPOFFER message that includes an available network address in the "ipaddr" field (and other configuration parameters in DHCP options). Servers need not reserve the offered network address, although the protocol will work more efficiently if the server avoids allocating the offered network address to another client. The server unicasts the DHCPOFFER message to the client (using the DHCP/BOOTP relay agent if necessary) if possible, or may broadcast the message to a broadcast address (preferably 255.255.255.255) on the client's subnet.
Incorrect Answers:
C. DHCP messages are broadcast to the "all hosts" address. IP multicast addresses are not used.
D. UDP is used, not TCP.
E. Since DHCP is used so that a client can obtain an IP address, a layer two destination address must be used, as the layer 3 IP address does not yet exist on the client for the return traffic.
F. DHCP, along with nearly every other type of traffic, requires the use of a transport layer protocol.
第4题：
Which protocol below uses TCP port 443?（）
- A、HTML
- B、HTTPS
- C、TFTP
- D、Telnet
- E、SMTP
正确答案:B
第5题：
What is the port number of the IPsec Authentication Header packet？（）
- A、IP protocol 50
- B、TCP port 51
- C、UDP port 50
- D、IP protocol 51
- E、UDP port 51
- F、TCP port 50
正确答案:D
第6题：
A.TCP is a transport layer protocol.
B.TCP is faster than the User Datagram Protocol (UDP).
C.TCP provides delivery notification and error checking mechanisms.
D.TCP uses a best effort delivery approach.
E.TCP application examples include HTTP and SMTP.
第7题：
What is the port number of an IPsec Encapsulating Security Payfoad packet？（）
- A、UOP port 50
- B、IP protocol 51
- C、TCP port 51
- D、TCP port 50
- E、IP protocol 50
- F、UDP port51
正确答案:E
第8题：
A.464
B.466
C.644
D.646
第9题：
Which two statements about SAN port channels configured on Cisco Nexus 5000 Series switches are true？ （）
- A、 The bring up protocol automatically detects and overrides any misconfiguration.
- B、 You can manually configure channel groups， or they can be automatically created.
- C、 Changes in configuration to the SAN port channel interface must also be made to all members of the channel group.
- D、 The port channel protocol uses the exchange fabric parameters command to communicate across peer ports in an ISL.
- E、 The port channel protocol ensures that a set of ports is eligible to be part of the same SAN port channel.
正确答案:B,E
第10题：
Which TCP port does LDP use for its protocol communications?（）
- A、464
- B、466
- C、644
- D、646
正确答案:D