多选题Which three security concerns can be addressed by a tunnel mode IPsec VPN secured by AH？（）Adata integrityBdata confidentialityCdata authenticationDouter IP header confidentialityEouter IP header authentication

第1题：

What does qos pre-classify provides inregardto implementing QoS over GRE/IPSec VPN tunnels？（）

• A、 enables IOS to copy the ToS field from the inner （original） IPheader to theouter tunnel IP header
• B、 enables IOS to make a copy of the inner （original） IP header and to run a QoS classification before encryption， based on fields in the inner IP header.
• C、 enables IOS to classify packets based on the ToS field in the inner （original） IP header
• D、 enables IOS to classify packets based on the ToS field in the outer tunnel IP header
• E、 enables the IOS classification engine to only see a single encrypted and tunneledflow to reduce classification complexity

第2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

第3题：

第4题：

What is not a difference between VPN tunnel authentication and per-user authentication?（）

• A、VPN tunnel authentication is part of the IKE specification. 
• B、VPN tunnel authentication does not control which end user can use the IPSec SA (VPN tunnel).
• C、User authentication is used to control access for a specific user ID, and can be used with or without a VPN tunnel for network access authorization. 
• D、802.1X with EAP-TLS (X.509 certificates) can be used to authenticate an IPSec tunnel.

第5题：

You need to configure a GRE tunnel on a IPSec router. When you are using the SDM to configurea GRE tunnel over IPsec， which two parameters are required when defining the tunnel interfaceinformation？（）

• A、The crypto ACL number
• B、The IPSEC mode （tunnel or transport）
• C、The GRE tunnel interface IP address
• D、The GRE tunnel source interface or IP address， and tunnel destination IP address
• E、The MTU size of the GRE tunnel interface

第6题：

During the Easy VPN Remote connection process，which phase involves pushing the IP address， Domain Name System （DNS），and split tunnel attributes to the client？（）

• A、mode configuration
• B、the VPN client establishment of an ISAKMP SA
• C、IPsec quick mode completion of the connection
• D、VPN client initiation of the IKE phase 1 process

第7题：

IPSec VPN is a widely-acknowledged solution for enterprise network. Which three IPsec VPNstatements are true？（）

• A、IKE keepalives are unidirectional and sent every ten seconds
• B、IPsec uses the Encapsulating Security Protocol （ESP） or the Authentication Header （AH）protocol for exchanging keys
• C、To establish IKE SA, main mode utilizes six packets while aggressive mode utilizes only threepackets
• D、IKE uses the Diffie-Hellman algorithm to generate symmetrical keys to be used by IPsec peers

第8题：

第9题：

Which three features are benefits of using GRE tunnels in conjunction with IPsec for building site-to-site VPNs？（）

• A、allows dynamic routing over the tunnel
• B、supports multi-protocol （non-IP） traffic over the tunnel
• C、reduces IPsec headers overhead since tunnel mode is used
• D、simplifies the ACL used in the crypto map
• E、uses Virtual Tunnel Interface （VTI） to simplify the IPsec VPN configuration

第10题：

Which QoS preclassification option will require the use of the qos pre-classify command for the VPN traffic？ （）

• A、VPN traffic needs to be classified based on the Layer2 header information
• B、VPN traffic needs to be classified based on the IP precedence or DSCP
• C、VPN traffic needs to be classified based on IP flow or Layer 3 information， such as source and destination IP address
• D、VPN traffic with Authentication Header （AH） needs to preserve the ToS byte