Download CCNA Security -Implementing Cisco Network Security (IINS v3-0).testkings.210-260.2019-05-23.1e.180q.vcex

Out-of-band refers to an interface that allows only management protocol traffic to be forwarded or processed. An out-of-band management interface is defined by the network operator to specifically receive network management traffic. The advantage isthat forwarding (or customer) traffic cannot interfere with the management of the router, which significantly reduces the possibility of denial-of-service attacks. 
Out-of-band interfaces forward traffic only between out-of-band interfaces or terminate management packets that are destined to the router. In addition, the out-of-band interfaces can participate in dynamic routing protocols. The service provider connects to the router’s out-of-band interfaces and builds an independent overlay management network, with all the routing and policy tools that the router can provide. 
Reference: http://www.cisco.com/c/en/us/td/docs/routers/asr9000/software/asr9k_r4-0/security/configuration/guide/b_sc40asr9kbook/b_sc40asr9kbook_chapter_0101.pdf

ACL-DEFAULT allows DHCP, DNS, ICMP, and TFTP traffic and denies everything else. 
Reference: http://www.cisco.com/c/en/us/td/docs/solutions/Enterprise/Borderless_Networks/Unified_Access/BYOD_Design_Guide/BYOD_Wired.html

The following table shows the relative security level provided by the recommended and NGE algorithms. The security level is the relative strength of an algorithm. An algorithm with a security level of x bits is stronger than one of y bits if x > y. If an algorithm has a security level of x bits, the relative effort it would take to "beat" the algorithm is of the same magnitude of breaking a secure x-bit symmetric key algorithm (without reduction or other attacks). The 128-bit security level is for sensitive information and the 192-bit level is for information of higher importance. 

  

Reference: http://www.cisco.com/c/en/us/about/security-center/next-generation-cryptography.html

The remaining four parts of the ESP are all encrypted during transmission across the network. Those parts are as follows:
The Payload Data is the actual data that is carried by the packet. 
The Padding, from 0 to 255 bytes of data, allows certain types of encryption algorithms to require the data to be a multiple of a certain number of bytes. The padding also ensures that the text of a message terminates ona four-byte boundary (an architectural requirement within IP). 
The Pad Length field specifies how much of the payload is padding rather than data. 
The Next Header field, like a standard IP Next Header field, identifies the type of data carried and the protocol. 
Reference: http://www.cisco.com/c/en/us/td/docs/net_mgmt/vpn_solutions_center/2-0/ip_security/provisioning/guide/IPsecPG1.html

These are the three different types of authentication supported by OSPF. 
Null Authentication—This is also called Type 0 and it means no authentication information is included in the packet header. It is the default. 
Plain Text Authentication—This is also called Type 1 and it uses simple clear-text passwords. 
MD5 Authentication—This is also called Type 2 and it uses MD5 cryptographic passwords. 
Authentication does not need to be set. However, if it is set, all peer routers on the same segment must have the same password and authentication method. The examples in this document demonstrate configurations for both plain text and MD5 authentication. 
Reference: http://www.cisco.com/c/en/us/support/docs/ip/open-shortest-path-first-ospf/13697-25.html

However, since iptables and Netfilter were introduced and connection tracking in particular, this option was gotten rid of. The reason for this is that connection tracking can not work properly without defragmenting packets, and hence defragmenting has been incorporated into conntrack and is carried out automatically. It can not be turned off, except by turning off connection tracking. Defragmentation is always carried out if connection tracking is turned on. 
Reference: http://www.iptables.info/en/connection-state.html

The following actions require the device to be deployed in Inline mode and are in affect for a user- configurable default time of 3600 seconds (60 minutes). 
Deny attacker inline: This action is the most severe and effectively blocks all communication from the attacking host that passes through the IPS for a specified period of time. Because this event action is severe, administrators are advised to use this only when the probability of false alarms or spoofing is minimal.
Deny attacker service pair inline: This action prevents communication between the attacker IP address and the protected network on the port in which the event was detected. However, the attacker would be able to communicate on another port that has hosts on the protected network. This event action works well for worms that attack many hosts on the same service port. If an attack occurred on the same host but on another port, this communication would be allowed. This event action is appropriate when the likelihood of a false alarm or spoofing is minimal.
Deny attacker victim pair inline: This action prevents the attacker from communicating with the victim on any port. However, the attacker could communicate with other hosts, making this action better suited for exploits that target a specific host. This event action is appropriate when the likelihood of a false alarm or spoofing is minimal.
Deny connection inline: This action prevents further communication for the specific TCP flow. This action is appropriate when there is the potential for a false alarm or spoofing and when an administrator wants to prevent the action but not deny further communication.  
Deny packet inline: This action prevents the specific offending packet from reaching its intended destination. Other communication between the attacker and victim or victim network may still exist. This action is appropriate when there is the potential for a false alarm or spoofing. Note that for this action, the default time has no effect.
Modify packet inline: This action enables the IPS device to modify the offending part of the packet. However, it forwards the modified packet to the destination. This action is appropriate for packet normalization and other anomalies, such as TCP segmentation and IP fragmentation re-ordering.
Reference: http://www.cisco.com/c/en/us/about/security-center/ips-mitigation.html

The I in CIA stands for Integrity — specifically, data integrity. The key to this component of the CIA Triad is protecting data from modification or deletion by unauthorized parties, and ensuring that when authorized people make changes that shouldn't have been made the damage can be undone. 
Reference: http://www.techrepublic.com/blog/it-security/the-cia-triad/

Stuxnet virus is part of cyber warfare unleashed by governments to hinder their opponents computer systems and steal vital information. 
Reference: https://en.wikipedia.org/wiki/Stuxnet

The read-only string attempted a write operation nine times as seen in the exhibit. It says, 9 illegal operations to community name supplied which means the read-only string attempted 9 write operations. 
Reference: http://www.cisco.com/c/en/us/support/docs/ip/access-lists/13608-21.html