Dynamic ARP Inspection (DAI) is a security feature that validates ARP packets in a network. DAI allows a network administrator to intercept, log, and discard ARP packets with invalid MAC address to IP address bindings. This capability protects the network from certain "man-in-the-middle" attacks. DAI determines the validity of an ARP packet based on valid IP to MAC address bindings from the DHCP snooping binding database. DAI also supports static ARP ACLs for hosts with static IP addresses. DAI checks all ARP packets on untrusted interfaces, and only forwards the packets that have valid bindings. DAI can also rate-limit the ARP packets on untrusted interfaces to prevent DoS attacks. The other options are incorrect because:
* B. In a typical network, DAI should be configured to make all ports as untrusted except for the ports connecting to trusted hosts or switches, which are trusted.
* C. DAI does not associate a trust state with each switch, but with each interface on the switch.
* D. DAI intercepts all ARP requests and responses on untrusted ports only, not on trusted ports.
References :=
https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst4500/12-2/25ew/configuration/guide/conf/dynarp.htm
https://study-ccna.com/dynamic-arp-inspection-dai/

We should scan emails using AntiVirus signatures to make sure there are no viruses attached in emails.
Note: A virus signature is the fingerprint of a virus. It is a set of unique data, or bits of code, that allow it to be identified. Antivirus software uses a virus signature to find a virus in a computer file system, allowing to detect, quarantine, and remove the virus.
SenderBase is an email reputation service designed to help email administrators research senders, identify legitimate sources of email, and block spammers. When the Cisco ESA receives messages from known or highly reputable senders, it delivers them directly to the end user without any content scanning. However, when the Cisco ESA receives email messages from unknown or less reputable senders, it performs antispam and antivirus scanning.
We should scan emails using AntiVirus signatures to make sure there are no viruses attached in emails.
Note: A virus signature is the fingerprint of a virus. It is a set of unique data, or bits of code, that allow it to be identified. Antivirus software uses a virus signature to find a virus in a computer file system, allowing to detect, quarantine, and remove the virus.
SenderBase is an email reputation service designed to help email administrators research senders, identify legitimate sources of email, and block spammers. When the Cisco ESA receives messages from known or highly reputable senders, it delivers them directly to the end user without any content scanning. However, when the Cisco ESA receives email messages from unknown or less reputable senders, it performs antispam and antivirus scanning.
We should scan emails using AntiVirus signatures to make sure there are no viruses attached in emails.
Note: A virus signature is the fingerprint of a virus. It is a set of unique data, or bits of code, that allow it to be identified. Antivirus software uses a virus signature to find a virus in a computer file system, allowing to detect, quarantine, and remove the virus.
SenderBase is an email reputation service designed to help email administrators research senders, identify legitimate sources of email, and block spammers. When the Cisco ESA receives messages from known or highly reputable senders, it delivers them directly to the end user without any content scanning. However, when the Cisco ESA receives email messages from unknown or less reputable senders, it performs antispam and antivirus scanning.
Reference:
b_ESA_Admin_Guide_12_0/b_ESA_Admin_Guide_12_0_chapter_0100100.html
-> Therefore Outbreak filters can be used to block emails from bad mail servers.
Web servers and email gateways are generally located in the DMZ so
Note: The recipient access table (RAT), not to be confused with remote-access Trojan (also RAT), is a Cisco ESA term that defines which recipients are accepted by a public listener.
b_ESA_Admin_Guide_12_0/b_ESA_Admin_Guide_12_0_chapter_0100100.html
-> Therefore Outbreak filters can be used to block emails from bad mail servers.
Web servers and email gateways are generally located in the DMZ so
b_ESA_Admin_Guide_12_0/b_ESA_Admin_Guide_12_0_chapter_0100100.html
-> Therefore Outbreak filters can be used to block emails from bad mail servers.
Web servers and email gateways are generally located in the DMZ so
Note: The recipient access table (RAT), not to be confused with remote-access Trojan (also RAT), is a Cisco ESA term that defines which recipients are accepted by a public listener.

The command "crypto isakmp identity address 172.19.20.24" is not valid. We can only use "crypto isakmp identity {address | hostname}. The following example uses preshared keys at two peers and sets both their ISAKMP identities to the IP address.
At the local peer (at 10.0.0.1) the ISAKMP identity is set and the preshared key is specified:
crypto isakmp identity address
crypto isakmp key sharedkeystring address 192.168.1.33
At the remote peer (at 192.168.1.33) the ISAKMP identity is set and the same preshared key is specified:
crypto isakmp identity address
crypto isakmp key sharedkeystring address 10.0.0.1
The command "crypto isakmp identity address 172.19.20.24" is not valid. We can only use "crypto isakmp identity {address | hostname}. The following example uses preshared keys at two peers and sets both their ISAKMP identities to the IP address.
At the local peer (at 10.0.0.1) the ISAKMP identity is set and the preshared key is specified:
crypto isakmp identity address
crypto isakmp key sharedkeystring address 192.168.1.33
At the remote peer (at 192.168.1.33) the ISAKMP identity is set and the same preshared key is specified:
crypto isakmp identity address
crypto isakmp key sharedkeystring address 10.0.0.1
Reference:
The command "crypto enrollment peer address" is not valid either.
The command "crypto ca identity ..." is only used to declare a trusted CA for the router and puts you in the caidentity configuration mode. Also it should be followed by a name, not an IP address. For example: "crypto ca identity CA-Server" -> Answer A is not correct.
Only answer B is the best choice left.
The command "crypto isakmp identity address 172.19.20.24" is not valid. We can only use "crypto isakmp identity {address | hostname}. The following example uses preshared keys at two peers and sets both their ISAKMP identities to the IP address.
At the local peer (at 10.0.0.1) the ISAKMP identity is set and the preshared key is specified:
crypto isakmp identity address
crypto isakmp key sharedkeystring address 192.168.1.33
At the remote peer (at 192.168.1.33) the ISAKMP identity is set and the same preshared key is specified:
crypto isakmp identity address
crypto isakmp key sharedkeystring address 10.0.0.1
The command "crypto enrollment peer address" is not valid either.
The command "crypto ca identity ..." is only used to declare a trusted CA for the router and puts you in the caidentity configuration mode. Also it should be followed by a name, not an IP address. For example: "crypto ca identity CA-Server" -> Answer A is not correct.
The command "crypto enrollment peer address" is not valid either.
The command "crypto ca identity ..." is only used to declare a trusted CA for the router and puts you in the caidentity configuration mode. Also it should be followed by a name, not an IP address. For example: "crypto ca identity CA-Server" -> Answer A is not correct.
Only answer B is the best choice left.