ccna 3 practice skills assessment part 1

ccna 3 practice skills assessment part 1.Any local host address (127.0.0.0/8).Any reserved private address (RFC1918,Address Allocationfbr PrivateInternets); Any address in the IP multicast address range (224.0.0.0/4). o The administrator should not release outbound packets whose source address is not a valid IP address for the internal network. The administrator can create an ACL that enables it to releasepackets whose source address is from within the network, but reject all other packets.4.1.8.3 Allowing Necessary Traffic Through the FirewallDNS, SMTP, and FTP are common services that should be allowed through the firewall.More commonly, the firewall also needs to be configured to allow some of the protocols required by the administrator to manage the router to pass through. For example, it is necessary to allow router maintenance traffic coming from external devices to pass through the internal router. Telnet. ssh. syslog and SNMP are all examples of services that need to be included in the router, with SSH always being preferred over Telneto keep in mind that while these services are useful, they should also be controlled and monitored, as vulnerabilities in these services can introduce security holes.4.1.8.4 Mitigating ICMP AbuseHackers use a variety of ICMP message types to attack networks. However, there is also management software that uses ICMP messages to gather information. Network management uses ICMP messages that are automatically generated by the router.Hackers can use ICMP echo packets to discover subnets and hosts on the protected network and use them to generate DoS flooding attacks. A hacker can use ICMP redirect messages to change the routing table of a host. Both ICMPecho and redirect messages should be blocked from entering the router.The following few ICMP messages facilitate proper network operation and should be allowed inbound.