CCNP Troubleshooting Flashcards
1
Q
Command: Display routing protocols status.
A
show ip protocols
2
Q
Command debug | EIGRP: displays all EIGRP messages that are sent and received on a router
A
debug eigrp packets
3
Q
Common reasons that the EIGRP adjacency fails follow:
A
- AS mismatch
- K value mismatch
- Misconfigured network command
- Passive interface
- Authentication misconfiguration
- Security filtering
- Unidirectional link
- Misconfigured subnet mask
4
Q
Command | EIGRP: Display interfaces that are running EIGRP
A
show ip eigrp interfaces
5
Q
Which command is used to verify the TCP connection for a BGP session?
A
show tcp brief | include 179
6
Q
You can use several methods at the same time. For the inbound updates, the order in which the methods are applied follows:
A
- Route-map
- Filter-list
- Prefix-list/distribute-list
7
Q
For the outbound updates the order follows:
A
- Prefix-list/distribute-list
- Filter-list
- Route-map
8
Q
Command: Display the BGP table. Add the summary keyword to display the status.
A
show ip bgp [summary]
9
Q
Command: Display the received routes by the BGP peer.
A
show ip bgp neighbors ip-address routes
10
Q
Command: Display the advertised routes by the BGP peer.
A
show ip bgp neighbors ip-address advertised-routes
11
Q
Command: Display information about the processing of BGP updates or display BGP events.
A
debug ip bgp {updates | events}
12
Q
There are several possible reasons for an erroneous clock on network devices:
A
- Access control lists do not permit UDP port 123 packets.
- An NTP authentication mismatch exists.
- Time zone and summer time misconfigurations are on the router.
- The time server is not accessible.
- The NTP server is misconfigured.
- The NTP server lost sync.
- High CPU utilization is present.
- A high offset is between the server and the client.
- The stratum is too high.
13
Q
NTP protocol and port number
A
NTP uses UDP port 123.
14
Q
NTP authentication method
A
MD5
15
Q
Command: Display the NTP status.
A
show ntp status
16
Q
Display the NTP associations
A
show ntp associations
17
Q
Display the NTP events that occur.
A
debug ntp events
18
Q
The server that is used to synchronize the clock is indicated with the ______ at the beginning of the line
A
asterisk (in the “show ntp association” output)
19
Q
For the inbound updates the order follows:
A
- Route-map
- Filter-list
- Prefix-list/distribute-list
20
Q
Command: Check if routing is enabled on the multilayer switch
A
show running-config | include ip routing
21
Q
Command: To add the DNS server IP address to the DHCP configuration
A
dns-server 209.165.201.209
22
Q
Command: DNS manual configuration in DNS client
A
ip name-server 209.165.201.209
23
Q
Command: renovar dhcp
A
renew dhcp ethernet 0/0
24
Q
Command: reload in certain time
A
reload in 15
25
Command: calcel programed device reload
reload cancel
26
DNS port
53 udp/tcp
27
FTP ports
20-21 tcp
28
Telnet port
23 tcp
29
SMTP port
25 tcp/udp
30
DHCP port
67-68 udp
31
TFTP port
69 udp
32
SNMP port
161-162 udp
33
Microsoft SQL ports
1433-1434
34
Command: replace the running configuration with the startup configuration, which will override, append, or delete configuration elements that are different.
configure replace startup-config
35
Command: The startup-configuration commands are added to the running configuration. However, commands that already exist in the running configuration but that are not in the startup configuration are not removed.
copy startup-config running-config
36
displays a summary of information about EIGRP address families
show eigrp plugins
37
EIGRP | reveals information for all address families that are configured.
show ip eigrp protocols
38
EIGRP | displays a list of network prefixes and the related information.
show eigrp address-family {ipv4 | ipv6} [autonomous-system-number] [multicast] accounting
39
EIGRP | displays an interface-specific configuration.
show eigrp address-family {ipv4 | ipv6} interfaces detail [interface-type interface-number]
40
EIGRP | displays information about all summary routes.
show eigrp address-family {ipv4 | ipv6} topology route-type summary
41
EIGRP | displays information on passive interfaces and a list of network prefixes.
show ip protocols and show running-config | section router eigrp
42
EIGRP | displays all packets except hellos.
debug eigrp packet terse
43
EIGRP | displays information about the stub status of the peer routers.
debug eigrp packet stub
44
EIGRP | The remote router advertises only its connected routes.
eigrp stub connected
45
EIGRP | The remote router advertises only its static routes.
eigrp stub static
46
EIGRP | The remote router advertises only other protocols and AS routes.
eigrp stub redistribute
47
EIGRP | The remote router advertises only summary routes.
eigrp stub summary
48
EIGRP | The remote router does not advertise routes.
eigrp stub receive-only
49
EIGRP | display the stub status of neighbors and which routes are advertised.
show ip eigrp neighbors detail
50
debug | to display all EIGRP packets except hellos.
debug eigrp packet terse
51
debug eigrp | display information about the stub status of the peer routers.
debug eigrp packet stub
52
check whether routing is enabled on the device using:
show ip route—no output means routing is not enabled.
show running-config—the lack of the "no ip routing" statement; cef statements: "ip cef" or "ipv6 cef" mean IP routing is enabled.
53
There are three ways to configure default route information on Layer 2 and multilayer devices:
- Switch# ip route 0.0.0.0 0.0.0.0 {ip-address | interface-type interface-number [ip-address]}
Use this command when routing is enabled on the device.
- Switch# ip default-network network-number
Use this legacy command when routing is enabled on the device.
- Switch# ip default-gateway network-number
Use this command on pure Layer 2 devices.
54
The recipe to application optimization is a four-step cycle
Step 1. Baseline application traffic.
Step 2. Optimize the network.
Step 3. Measure, adjust, and verify.
Step 4. Deploy new applications.
55
Netflow | The seven fields that need to match for packets to be considered part of the same flow are as follows:
* Source IP Address
* Destination IP Address
* Source Port (protocol dependent)
* Destination Port (protocol dependent)
* Protocol (Layer 3 or 4)
* Type of Service (ToS) Value (differentiated services code point [DSCP])
* Input Interface
56
To implement IP SLA network performance measurement, you need to perform the following tasks:
* Enable the IP SLA responder, if required.
* Configure the required IP SLA operation type.
* Configure any options available for the specified operation type.
* Configure threshold conditions, if required.
* Schedule the operation to run, and then let the operation run for a period of time to gather statistics.
* Display and interpret the results of the operation using the Cisco IOS CLI or an NMS, with SNMP.
57
For Cisco AutoQoS to work certain requirements must be met, as follows:
* CEF must be enable on the interface.
* The interface (or subinterface) must have an IP address configured.
* For serial interfaces (or subinterfaces) configure the appropriate bandwidth.
* On point-to-point serial interfaces, both sides must be configured AutoQoS.
58
Troubleshooting performance problems is a three-step process:
Step 1. Assessing whether the problem is technical in nature
Step 2. Isolating the performance problem to a device, link, or component
Step 3. Diagnosing and resolving the performance degradation at the component level
59
The following events cause spikes in the CPU utilization:
* Processor-intensive Cisco IOS commands
* Routing protocol update processing
* SNMP polling
60
Some common interface and wiring problems are as follows:
* No cable connected
* Wrong port
* Device has no power
* Wrong cable type
* Bad cable
* Loose connections
* Patch panels
* Faulty media converters
* Bad or wrong GBIC
61
Common symptoms of a router CPU that is too busy is that the router fails to respond to certain service requests. In those situations, the router might exhibit the following behaviors:
* Slow response to Telnet requests or to the commands issued in active Telnet sessions
* Slow response to commands issued on the console
* High latency on ping responses or too many ping timeouts
* Failure to send routing protocol packets to other routers
62
When troubleshooting CEF, you always want to check and verify the following:
* Is CEF enabled globally and per interface?
* Is there a FIB entry for a given network destination?
* Is there a next hop associated with this entry?
* Is there an adjacency entry for this next hop?
63
Symptoms of memory-allocation failures include the following:
* Messages such as %SYS–2–MALLOCFAIL: Memory allocation of 1028 bytes failed from 0x6015EC84, Pool Processor, alignment 0 display in the router logs.
* Not getting any output from show commands.
* Receiving Low on memory messages.
* Receiving the message Unable to create EXEC – no memory or too many processes on the console.
64
Some of the main reasons for memory problems are as follows:
* Memory size does not support the Cisco IOS Software image
* Memory-leak bug
* Security-related problems
* Memory-allocation failure at process = interrupt level error message
* Buffer-leak bug
