Free Practice Questions for Cisco 300-410 Exam

Let’s see how the “logging synchronous” command affect the typing command:

Without this command, a message may pop up and you may not know what you typed if that

message is too long. When trying to erase (backspace) your command, you realize you are

erasing the message instead.

With this command enabled, when a message pops up you will be put to a new line with your

typing command which is very

After redistribution, R3 learns about network 10.1.1.0/24 via two paths:+ Internal BGP (IBGP): advertised from R4 with AD of 200 (and metric of 0)+ OSPF: advertised from R1 with AD of 110 (O E2) (and metric of 20)Therefore R3 will choose the path with the lower AD via OSPF

But this is a looped path which is received from R3 - > R2 - > R1 - > R3. So when the advertised route from R4 is expired, the looped path is also expired soon and R3 willreinstall the main path from R4. This is the cause of intermittent connectivity.In order to solve this issue, we can lower the AD of iBGP to a value which is lower than 110 so that it is preferred over OSPF-advertised route.

Disable-connected-check enables a directly connected eBGP neighbor to peer using a loopback address without adjusting the default TTL of 1. In disable connected check the router does not decrease the TTL of an IP packet that is destined to itself so it only counts or considers as one hop between the two loopbacks of the routers.

Explanation

From the last line of the output, we notice that the result was “Invalid AUTHEN packet”. Therefore something went wrong with the username or password.

R1(config)#int tunnel 1

R1(config-if) no ip split-horizon eigrp 100

Overview of the IPv6 First-Hop Security Binding Table

A database table of IPv6 neighbors connected to the device is created from information sources such as NDP snooping. This database, or binding table, is used by variousIPv6 guard features to validate the link-layer address (LLA), the IPv4 or IPv6 address, and the prefix binding of the neighbors to prevent spoofing and redirect attacks.

IPv6 First-Hop Security Binding Table Recovery MechanismThe IPv6 first-hop security binding table recovery mechanism enables the binding table to recover in the event of a device reboot.

After redistribution, R3 learns about network 10.1.1.0/24 via two paths:

+ Internal BGP (IBGP): advertised from R4 with AD of 200 (and metric of 0)

+ OSPF: advertised from R1 with AD of 110 (O E2) (and metric of 20)

Therefore R3 will choose the path with the lower AD via OSPF

But this is a looped path which is received from R3 - > R2 - > R1 - > R3. So when the advertised route

from R4 is expired, the looped path is also expired soon and R3 will reinstall the main path from R4.

This is the cause of intermittent connectivity.

We can solve this problem by denying the 10.1.1.0/24 prefix from being redistributed into OSPF on

R1. So R3 will not learn this prefix from R1.

Or another solution is to place an OSPF distribute-list inbound on R3 to block the 10.1.1.0/24 prefix

from being advertised back to R3.

If you configure the redistribution of OSPF into BGP without keywords, only OSPF intra-area

and inter-area routes are redistributed into BGP, by default. You can use the internal keyword

along with the redistribute command under router bgp to redistribute OSPF intra- and inter-area

routes.

Use the external keyword along with the redistribute command under router bgp to redistribute

OSPF external routes into BGP.

- > In order to redistribute all OSPF routes into BGP, we must use both internal and external

keywords. The full command would be (suppose we are using OSPF 1):

redistribute ospf 1 match internal external

Note: The configuration shows match internal external 1 external 2. This is normal because

OSPF automatically appends “external 1 external 2” in the configuration. In other words,

keyword external = external 1 external 2. External 1 = O E1 and External 2 = O E2.

A Multiprotocol Label Switching(MPLS) Layer 3 Virtual Private Network (VPN) consists of a set

of sites that are interconnected by means of an MPLS provider core network. At each customer

site, one or more customer edge (CE) routers attach to one or more provider edge (PE) routers.

https://www.cisco.com/c/en/us/td/docs/cloud-systems-management/network-automation-and management/dnacenter/tech_notes/b_dnac_sda_lan_automation_deployment.html