Reduced network downtime
Faster time to resolution of problems
Simplified troubleshooting processes
Predictable lead times for change requests
Maintenance windows during regular business hours
Black hole VLAN
The user successfully gained access to the router EXEC shell.
The user attempts to gain access to a local security server were unsuccessful.
The user credentials were rejected by the default authentication method.
The user access to the services was stopped because of the improper protocol that was used for the session.
High CPU usage on the router
Insufficient RAM in the router
Incorrect or outdated version of the Cisco IOS
Unrecognized Layer 2 encapsulation formats on the network
Any traffic that is going through a GRE tunnel
Any traffic that is explicitly blocked by an ACL
Any traffic that is destined for any of the switch IP addresses
Any traffic that is assigned to a particular VLAN that is not allowed on a trunk
Any traffic that is coming to an inbound port that is in the spanning-tree blocking state
Any multicast and broadcast traffic that is coming from the Spanning Tree Protocol (STP) or routing protocols
Change the seed metric of the routes being redistributed.
Filter the routes being redistributed between the protocols.
Redistribute all subnets in both EIGRP and OSPF domains
Configure an additional router to be a secondary point of route redistribution
Port Fa0 / 20 will be shut down.
Port Fa0 / 20 will become a root port.
Port Fa0 / 20 will start forwarding traffic immediately
Port Fa0 / 20 will transition from blocking to forwarding state after the spanning tree convergence
Network maintenance typically excludes consideration of network changes
Proper network maintenance will eliminate network downtime.
Maintaining network documentation is an important element of network maintenance.
The amount of resources expended on network maintenance is consistent across all companies.
R1 (config) # ip route 0.0.0.0 0.0.0.0 172.16.7.1
R1 (config) # ip route 172.16.6.0 255.255.255.0 172.16.7.10
R2 (config) # ip route 172.16.6.0 255.255.255.0 172.16.7.9
R2 (config) # ip route 0.0.0.0 0.0.0.0 172.16.7.9
R3 (config) # ip route 0.0.0.0 0.0.0.0 172.16.7.9
R3 (config) # ip route 172.16.6.0 255.255.255.0 172.16.7.10
Testing the hypothesis
Documenting the changes
Eliminating possible causes
Issue the show mac address-table address 0011.9254.e2a0 command on various switches and follow the path to the host
Issue the show vlan command on various switches and follow the path to the host.
Issue the traceroute 0011.9254.e2a0 command and follow the path to the host.
Issue the traceroute 10.10.10.251 command and follow the path to the host.
Route redistribution information
BGP related events
Phases of BGP peering relationships
Internal metrics of IBGP routes
The TACACS + server is not operational.
The TACACS + server IP address has been incorrectly configured on the router.
The TACACS + server key of the router does not match that of the TACACS + server.
The username and password that were supplied by the user were rejected by the TACACS + server.
The DHCP server sends a DHCPOFFER message with the full set of configuration parameters to the client.
The DHCP client sends out a DHCPDISCOVER broadcast message to find its local DHCP server.
The DHCP server sent a DHCPACK message with the full set of configuration parameters to the client.
The DHCP client sends out a DHCPREQUEST broadcast message to the DHCP server to accept the offered parameters.
Provide an effective method of maintaining network documentation
Ensure that all individuals carry out similar tasks in a consistent manner
Document the solution to specific problems eliminating the requirement for troubleshooting
Allow each technician to select the best troubleshooting process to use for a particular problem
Ensure that the problem is located and corrected regardless of the knowledge level of the technician
Client or server
Client or transparent
Transparent or server
A routing error
An access list error
Duplicate MAC addresses
VLAN trunk misconfiguration
A Spanning Tree Protocol related issue
All NetFlow packets sent from R1 to the traffic collector will be sourced from IP address 22.214.171.124.
Interfaces Fa0 / 0 and Fa0 / 1 must also be included as flow-export source interfaces.
NetFlow version 5 should be configured if the infrastructure includes non-Cisco devices.
NetFlow will track all ingress traffic for interfaces Fa0 / 0 and Fa0 / 1.
NetFlow will forward the traffic statistics and packet payload content of interfaces Fa0 / 0 and Fa0 / 1 to IP address 10.10.10.1.
The UDP value 9996 is optional because it is the default NetFlow destination port number.
The NAT pool is exhausted.
The static translation any any new dynamic translations
The ACL is using a wrong pool reference
The R2 LAN is not configured as an inside interface.
Interface FastEthernet 0/0 on router R1 requires the vrrp 1 ip 10.1.1.254 command to be issued
Interface FastEthernet 0/0 on router R1 requires the vrrp 1 preempt command to be issued.
Interface FastEthernet 0/0 on router R1 requires the vrrp 1 priority 100 command to be issued.
Router R1 is configured to use text authentication, while R2 is configured to use MD5 authentication.
Router R1 should be configured to use text authentication.
The EIGRP neighbor has not sent any hello packets in the last 14 seconds.
The EIGRP neighbor is redistributing routes from OSPF with invalid seed metrics.
The EIGRP neighbor is offline and unreachable.
The Q Cnt field should be at zero.
The Seq Num field should be much higher.
The values of the SRTT and RTO fields should be much lower.
RTB did not see its router ID in the hello packet that was received from RTA.
RTB did not receive a hello packet from RTA.
RTB is able to exchange routing updates with RTA
RTB has established an adjacency with RTA.
Map the DLCI to the link local address of R2.
Change the OSPF neighbor to point to the global unicast address of R2.
Change the IPv6 address on Serial 0/0/0 to be in the same segment as the Serial 0/0/0 interface of R2.
Remove the broadcast keyword from the frame-relay map statement.
A static route should be added to R3 to point to the 192.168.1.0/24 network.
A static route should be added to R1 to point to the 192.168.1.0/24 network
The tunnel source for Tunnel0 on R3 should be the IP address of Serial0 / 0/1 on R1.
The tunnel source for Tunnel0 on R1 should be the IP address of Loopback0 on R3.
The tunnel destination for Tunnel0 on R1 should be the IP address of Serial0 / 0/1 on R3.
The tunnel destination for Tunnel0 on R3 should be the IP address of Loopback0 on R1.
The STP reaches its maximum diameter.
Ports that should be blocked start forwarding.
The TTL field in the Ethernet frames decrements to 0 on all frames.
Frames with matching entries in the MAC address table are not forwarded.
QoS is not supported in Lightweight mode.
The trunk between R1 and SW1 does not support QoS.
SW1 is resetting the DSCP values supplied by the Lightweight AP.
The Wireless LAN Controller has not been configured to support voice traffic.
QoS has not been enabled between the Lightweight AP and the Wireless LAN Controller.