Review Question #2

[Stevep]

Todd, I can get the same result from all four of the answers in question #2. Although B. might not be current if changes were made and the startup-config not upated but they will all give the ip/CIDR. Yet, show ip protocol yields nothing. I would think A, C and D would be equal.

Cisco-831#show ip protocols

Cisco-831#

Cisco-2600#show ip protocol

Cisco-2600#

[aguilera]

Chapter 4, Question 2, page 242.

You need to find the broadcast address used on a LAN on your router. What command will you type into the router from user mode to find the broadcast address?

So we want to find a broadcast address by examining a router right?

Ok,

A. show running-config: This command will show us the current IP and Mask for any configured interface.

B. show startup-config: This command will show us the IP and Mask used on an interface at startup.

C. show interfaces: This command will show us the IP and mask configured on an interface.

Hey, that makes A, B, and C correct so far right? :) Wrong! :( What?:confused:

Let's take a look at the question again.... "What command will you type into the router from user mode..." Oh, user mode. Show run and Show start are privilege level commands.

The only user mode commands listed are C and D.

We have already determined that C is a correct answer. Let's examine D.

D. show protocols: This command tells us what routed protocols are enabled and the IP and Mask associated with active or inactive interfaces.

Here is the output of the Show protocols command:

http://www.FidelisNetworks.com/shprot.jpg
So guess what.... C and D are the correct answers.

Let's take a look at the answer listed on page 247.

The answer only lists C, but should also include D. Todd has been made aware of this and appreciates your attention to detail!

Oh, one more thing... the show ip protocols command does not give broadcast information as described on page 247. It is the show protocolscommand that gives that output.

Thanks for such a great question and leading us to make some corrections in the book!

D. Aguilera

[Stevep]

D. Aguilera, Excellent clarification!
I didn't notice user mode in the question, :oops: that is a killer! That alone would have narrowed my choices to C or D. Thanks, I'll read more carefully from now forward.

[pinguino001]

Hi Todd/Aguilera/all,
I tried the possible answers of the question 2 you've talked about.
The problem is that the command show protocols is not working on
USER mode as show below:

Router>
Router>en
Router#conf
Configuring from terminal, memory, or network [terminal]?
Enter configuration commands, one per line. End with CNTL/Z
Router(config)#int f0/0
Router(config-if)#
Router(config-if)#ip address 192.168.1.64 255.255.255.0
Router#disable
Router>show interfaces

FastEthernet0/0 is administratively down, line protocol is down
Hardware is AmdFE, address is 00b0.adf0.b858 (bia 00b0.adf0.b85
Internet address is 192.168.1.64/24
-cut-

--More--
Router>
Router>show protocols
^
% Invalid input detected at '^' marker.
Router>en
Router#show protocols
Global values:
Internet protocol routing is enabled
Serial0/1 is administratively down, line protocol is down
Serial0/0 is administratively down, line protocol is down
FastEthernet0/1 is administratively down, line protocol is down
FastEthernet0/0 is administratively down, line protocol is down
Internet address is 192.168.1.64/24

Router#show ip protocols

Router#show ip protocol

Router#disable
Router>show ip protocol

Router>

So the command show interfaces is the only correct answer,isn't it?
Or not? :confused: I'm very confused about it ! :confused:

Please could you tell me how have you got the dos screen in your post
and if I missed something in my tests?
Please consider that I'm using CCNA Virtual lab simulator,platinum edition.

Many thanks
/marco

[lammle]

The only correct answer is C: Show interfaces, as the answer shows. However, in my explanation, I mention that show ip protocols would show us this information and this is not true. Show protocols would, which is answer D, so C and D are correct. What I meant to do was use show ip protocols as answer D, which would then make only answer C correct, then say "show protocols would be a correct answer, too bad it isn't a possible answer"....but I got them backwards....oops!

The DOS screen shows up in the output because Dan was using Telnet to get into a router.

Cheers!
Todd Lammle

[tsunamoro]

Hi all.

Very interesting clarification. But still a problem (for me) remains.

According to the "help" in the routers and switches (I have tried with a real switch) and the IOS documentation (12.2 and 12.4), show interfaces and show protocols (and also show controllers) are commands in the privileged mode, but they work also in user mode.
I've tried to find out more, and in IOS 10.0, and probably before 12.2, the commands are usable both in user and privileged mode.
Because in all the example in the book, all the show commands are used in privileged mode, was your intention Todd to "push" us to discover which commands can be used also (and only) in user mode?

Another point. I found out that exists another command that could be useful and work in user mode (and is correctly showen in my switch): show ip interface. What do you think about this command?

Anyway, this question (or better the possible solutions) is very tricky (Todd, it's not your fault :) ).

Bye.

PS For anyone wants to know why show ip protocols doesn't work, it's because this command shows the active routing protocols. No routing protocol, blank output!

[Pravin]

Hi Aguilera,

Could you clarify please?

In your response to Stevep, you mention "show ip protocols command does not give broadcast information as described on page 247. It is the show protocols command that gives that output".

I've tried the Show Protocol command. This gives me the IP Address but not the Broadcast. However, when I type in the command "Show IP Interface", this gives me the broadcast address output. Is this what you mean't?

Thanks,

Pravin.

[lammle]

I try and make sure that every student in ny cisco class use all the possible show commands for verifcation and troubleshooting. Everything but the show running-config command.

You need to be able to verify/troubleshoot the network without looking at the configuraiton. Here is a brief description of the most commonly used commands:

show ip interface brief is a great place to start to verify your ip addresses and status of the interfaces, but not the subnet masks.

show ip interface shows the ip default configurations on the interface, including the ip address, mask, broadcast address, access lists if set, as well as the status of each interface, but not in a single brief page

show protocols will show you your ip addreses and masks for each interface, but not the status.

show ip protocols will show you routing information configured on your router.

show ip route shows the routing table

show cdp neighbors will show you the directly connected devices, the hostnames, interfaces and type of device

show cdp neighbors detail will show you everything that the show cdp neighbors command does, plus the ip address of the directly connected devices.

There are many more, but these are the typical show commands that can be used to easily verify and troubleshoot your network.

Cheers!
Todd Lammle

[Pravin]

Thanks for the explanation Todd, much appreciated.

Pravin.