ccna 200 301 exam

ccna 200 301 exam.Routing is working fine, but some of the filters, such as IPV6ACL,are dropping packets.Although IPv6 ACLs are not discussed in this book or in ICND1, ICND1 does discuss IPv4 ACLs. The IPv6 ACL is extremely similar in principle, but of course it filters IPv6 packets rather than IPv4 packets. IPv6 ACL Configuration Definitions16.2 Base Content 347 shows a list of statements, each matching the source and destination IPv6 address ranges, port numbers, and so on. You can enable ACLs, which filter IPv6 packets as they flow in or out of an interface.For example, Figure 16-19 shows a line of (syntactically correct) IPv6ACLs. ipv6ACLs define the source and destination address ranges as address/prefix pairs, just like the ipv6addressinterface subcommand. To filter Telnet traffic on the network from subnet I to subnet 3, you can add the ACL to any of the four locations marked with arrowed lines in the figure. (Note that the ACL also requires some other statements that allow other traffic.)Subnet 1 Subnet 3 2001:DB8:1111:1::/64 2001:DB8:1111:3::/64 172.16.3.1Deny tcp 2001:DB8:1111:1::/64 2001:DB8:1111:3::/64 ea 23tftSource IP Destination IP Destination Port Figure 16-19 Filtering IPv6 Packets Based on Destination Port Before you read more about troubleshooting, take a closer look at the one-line ACL example. The address range is determined by the IPv6 prefix (subnet), which in turn is calculated based on the address and prefix length. Therefore, this ACL would define a source address range for subnet 1 (2001:DB8:lllll:l::/64) and a destination address range in subnet 3 (2001:DB8:lllll:3::/64). It also lists the destination port for 23 (Telnet). Then, with a deny action, the ACL command drops the IPv6 Telnet stream. Now let's move on to the topic of troubleshooting. In short, when you see a symptom of a suspected routing problem, check to see if any IPv6ACLs are enabled. On an IPv4 router, the command used to check for any enabled ACLs is showipinterfaceo then, for IPv6, you can use show ipv6 interface,,Example 16-8 shows this command applied to a router, with the shaded lines marking the IPv6ACLs that are enabled0Example 16-8 The showipv6interface command on Router R2R2# show ipv6 interface