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CCNA book amusements, part 2

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Dec. 20th, 2009 | 11:21 pm
location: Home, Chicago, IL
Music: Fluke - Puppy

More of the same.

"This is one reason why OSPF is more fun than other routing protocols--it gives us all a lot more ways to screw things up!" -- Chapter 6. This is after ~30 pages of "oh man, EIGRP is great. The only reason you wouldn't use it is if you have non-Cisco equipment in your network, and why would you do that?" (paraphrased).

I don't think this is a sane question. But, I guess that's why I'm not the one writing the book!:
"A switch has been configured for three different VLANs: VLAN2, VLAN3, and VLAN4. A router has been added to provide communication between the VLANs. What type of interface is necessary on the router if only one connection is to be made between the router and switch?
A. 10Mbps Ethernet
B. 56Kbps Serial
C. 100Mbps Ethernet
D. 1Gbps Ethernet"
The answer is C, because you need 100Mbps or 1Gbps. Why? Not really discussed. Note that the question wasn't "what is the minimum link that will work", or anything like that. Chapter 9.

"If you do yoga, meditate, chain smoke, or consume mass quantities of comfort food when stressed, take a little break and do that now because, and I'm going to be honest, this isn't the easiest part of the chapter--or even the book, for that matter." Chapter 9, about voice VLANs.

"But do you really want to deny MAC addresses? Doesn't this sound like a bad hangover before you even start? While it's true there are special circumstances where you would, there is another option, and I think it's usually the better one: Just deny access based on the ether-type field in the Ethernet frame header instead." -- Chapter 10. How are those even the same?

"But who actually uses DecNet and AppleTalk? They definitely deserve to be denied access to your beautiful, well-oiled network, don't they?" -- Chapter 10. WTF.

"It won't tell you when or how the NASDAQ's gonna bounce up and down like a superball, but ESP will provide confidentiality, data origin authentication, connectionless integrity, anti-replay service, and limited traffic-flow confidentiality by defeating traffic flow analysis. Which is almost as good!" -- Chapter 14. No, I'm not leaving any context out, that's how the section starts.

... I'm done for the night.

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Comments {8}

Jarrod Lombardo

(no subject)

from: jaberwockynmt
date: Dec. 21st, 2009 05:51 am (UTC)
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He says "necessary" when he means "sufficient." You may have to consider that substitution on the actual test questions.

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wolf359nmt

(no subject)

from: wolf359nmt
date: Dec. 21st, 2009 07:54 am (UTC)
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Fuck you Pintsize. Math tastes like electricity...oh you are a robot.

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wolf359nmt

(no subject)

from: wolf359nmt
date: Dec. 21st, 2009 07:58 am (UTC)
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Oh wait, that's not Pintsize. Pintsize has the potential to have HUGE THUMBS.
I've had insufficient sleep.

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hamster

(no subject)

from: cavehamster
date: Dec. 21st, 2009 08:03 am (UTC)
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I could be wrong, but wasn't with the ratification of the 100Mb/s standard that the 4 byte VLAN tag was added to the Ethernet frame? I know, unrelated, that Jumbo Frames only exist at 1Gb/s and higher, but I seemed to recall something about VLANs as well.

Not to say you can't VLAN other links, but only in an untag fashion.

I agree doing MAC-based auth is a headache waiting to happen, but I have no clue what he is getting on about there.

Appletalk was certainly headed on the way out, until Apple came out with OSX Server and made filesharing happen by default via Appletalk. It's a pain in the ass, though, when your Appletalk zone fragments without you knowing it and a printer goes off the deep end... grrr.

Sounds like some book. I've never bothered with the CCNA, I just end up reading the docs or googling when I need to setup something moderately complex. Cisco annoys me to no end, but they usually make good equipment, and the CLI interface is awesome. That said, it seems like every rev of IOS, and man... there are like 40000000000000 of them, breaks the things it fixed 2 revs back. Ugh. I still have my account tagged on TAC with the Motorola global account number, so I have access to anything I wish to download. Woot. Just need some Cisco gear now... hehe.

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Bill Weiss

(no subject)

from: houdini_cs
date: Jan. 3rd, 2010 03:03 am (UTC)
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I didn't take it to learn anything, I just needed it for work.

If you want some Cisco junk to play with, I've got a nice emulator if you just want to play. Email me if you're interested.

I have no idea when VLANs became part of the standard. I know we were doing it on 100M links in class.

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flainn

(no subject)

from: flainn
date: Dec. 21st, 2009 03:25 pm (UTC)
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Damn, I wish my Microsoft books were half as amusing.

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Baron El Dorado, First Earl of Dorkitude

(no subject)

from: baronj
date: Dec. 21st, 2009 04:44 pm (UTC)
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Ah, yes. EIGRP and OSPF; How to fuck your network over in a heartbeat. And let's not hear about vlan asshattery: the reason why the answer is "MOAR BANDWIDTH" is because your fucking phones are taking away all the rest of my traffic. Oh, that's chapter nine, good. "Quality of Service" is marketreese for "buy our VoIP or else", or alternately "Nice traffic-map you got there; shame if anything were to happen to it..."

And never, NEVER NEVER take security advice from a CCNA anyway; get a real cert for that. Or just have a brain. CCNAs are like first lieutenants with a map and a compass: Dangerous alone.

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Bill Weiss

(no subject)

from: houdini_cs
date: Jan. 3rd, 2010 03:01 am (UTC)
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OSPF can be ok if you're running it over a small segment (to make a poor-man's hardware failover, for instance).

I'm unclear on why voice VLANs are different from VLANs. I mean, yeah, all your Cisco gear can auto-negotiate it without you configuring it (ahem), but so what?

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