DIAG

HSRP:
====

Cause: CE1
Resolution: increase CE1's hsrp priority
Wireshark: Select the first HSRP negotiation packet

CE1 is HSRP Standby with nd-preference High
CE2 is HRSP Active with nd-preference Low


MCAST:
======

#1 root-cause of the issue?
 "no route to reach RP from R3"

 #2 what is the info needed from L1 engineeer to confirm the root-cause?
 "why is '10.1.4.1' not found in RIB table in R3"

 #3 quick Fix
 "ip route 10.1.4.1 255.255.255.255 10.0.0.17"


Port-Security:
=============

Part - 1.1 : Which switch has the problem?
Answer : Select device SW3
Part - 1.2 : Which command to use for identifying the problem?
Answer : Show ip int brief

Part 2.1 : Which Device has the problem?
Answers : Select device Host-1
Part 2.2 : Which command to use for identifying the problem?
Answers : MAC address of interface Ex/x

VTP:
====

Part - 1.1 : Which switch has the problem?
Answer : Select device SW3
Part - 1.2 : Which command to use for identifying the problem?
Answer : Show vtp status

Part 2.1 : Which Device has the problem?
Answers : Select device Sw3
Part 2.2 : Which command to use for identifying the problem?
Answers : Show vtp password(ask for vtp password)

DMVPN-1:
=======
*In Logs you can see " Midchain parent maintenance for IP Midchain out of Tunnel0, addr X.X.X.X - looped chain attempting to stack" (X.X.X.X address is R15's NBMA address)

Part 3.1 : Which Device we will select?
R15

Part 3.2 : Which command to use for identifying the problem?
Device: Redistribute connected
Command Line: exclude (e0/0) nbma from eigrp

DMVPN-2:
=======

On Site A, the R16 interface E1/0 is configured with /29 network. It should be configured with /30 mask

Part 3.1 : Which Device has the problem?
Select Device: R16

Part 3.2 : Which command to use for identifying the problem & What is the resolution?
Device: Show ip int brief
Command Line: Increase the subnet mask length to /30

URPF:
====

When a packet is received at the interface where Unicast RPF and ACLs have been configured, the following actions occur:

Step 1 Input ACLs configured on the inbound interface are checked.

Step 2 Unicast RPF checks to see if the packet has arrived on the best return path to the source, which it does by doing a reverse lookup in the FIB table.

Step 3 CEF table (FIB) lookup is carried out for packet forwarding.

Step 4 Output ACLs are checked on the outbound interface.

Step 5 The packet is forwarded.

Config Sectipon 5

R17:
===


R17#show running-config | sec flow
 ip flow ingress
ip flow-export version 9
ip flow-top-talkers
 top 10
 sort-by bytes
 cache-timeout 10
 match source address 123.20.1.9 255.255.255.255
 match output-interface Tunnel0
 match protocol 1

R17#
*Jan  6 18:26:23.476: %SYS-5-CONFIG_I: Configured from console by console
R17#sh ip flow top-talkers

SrcIf         SrcIPaddress    DstIf         DstIPaddress    Pr SrcP DstP Bytes
Et0/2         123.20.1.9      Tu0           123.19.19.19    01 0000 0800   500
1 of 10 top talkers shown. 1 of 6 flows matched.


NTP:
===
[06/01/16 7:53:55 pm] Con: show ntp status -> you will see
Clock is synchronized, stratum 4
[06/01/16 7:54:25 pm] Con: client's stratum = (Server's stratum) + 1