300-410 Exam Dumps - Implementing Cisco Enterprise Advanced Routing and Services (300-410 ENARSI)

The error “Administratively disabled” means we need to enable SCP on the router with the command: Router(config)#ip scp server enable

The configuration on NY router is good for OSPF authentication. So we must enable OSPF

authentication on LA router with the following commands:

router ospf 1

area 0 authentication message-digest

interface E0/0

ip ospf message-digest-key 1 md5 Cisco123

https://www.cisco.com/c/en/us/support/docs/ip/open-shortest-path-first-ospf/13684-12.html

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.

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 a router is configured to get the time from a Network Time Protocol (NTP) server, the times in the router’s log entries may be different from the time on the systemclock if the [localtime] option is not in the service timestamps log command. To solve this issue, add the [localtime] option to the service timestamps log command. Thetimes should now be synchronized between the system clock and the log message timestamps.

https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3750/software/release/122_55_se/configuration/guide/scg3750/swv6acl.html

https://www.cisco.com/c/en/us/td/docs/switches/datacenter/sw/5_x/nx-os/mpls/configuration/guide/mpls_cg/mp_mpls_overview.pdf