all entries in category 'cisco'

The holidays are over . . . this much is evident in the dull, lifeless days I have been subjected to of late, but one ray of light does seem to shine through; my CCNA class started up again yesterday. Yes, despite the rigmarole involved in registering for this class, I got in -- and I have a feeling that this unit will be the most interesting and pertinent of the bunch. For one thing, the AACC IT staff finally got its headquarters out of its hindquarters and sorted out the computers in the classroom. Well, enough that it makes our lives as students a tad less annoying (to wit, not having to disassemble the entire classroom network to plug in a router). Nice to see they actually sat down for five minutes and thought about who and what would be using the alloted space. There is also the quite pleasant matter of the the drastic reduction in tuition: the last two units (of four) were an even grand a piece, and now they are just over four hundred. You see, the over-arching goal is preparation for the CCNA test which is given by an independent testing entity, not the school. Heretofore the school offered only CEU's -- Continuing Education Units for our hard work -- which, exactly as you might assume, are about as useful as a paper cup full of warm spit. Aha -- but now, as a result of our professor's efforts, the class is now on the credit side of the university, and there's even talk of retroactivity to this policy change -- to quote Carl Spackler¹: "So I got that goin' for me, which is nice."

For the first class, we broke out the routers to do a little password recovery drill - I must say I was rusty at the ol' terminal, but I came around pretty fast. One thing I need to remember to do is to figure out how to get Linux to let me use my laptop's serial port (***note to self: look into Minicom and /dev/ttys0/.***) so I don't have to screw around with the desktop computer too much, and I can save my configurations right on my lappy.

We had a nice discussion of access control lists - the rules that routers use to permit or deny traffic, and generally one of the more confusing and head-cramping aspects of the class so far. I must say, however, that a christmas gift I received is helping me a lot: It is a book called Cisco IOS In a Nutshell, and it only took me five minutes of listening to the lecture to realize how much of a godsend this book is. I was messing around last night, trying to put my current firewall's settings for this web server into an ACL as practice. Here's what I came up with:
Not at all sure if that is correct -- these little buggers can be confusing. I bet I'd probably give up the farm or bring down my site if I had to use a Cisco router at home, but I guess that is why I am paying to learn this stuff. I know most of the people who read my journal are probably either put-off by the previous passage, and I apologize; but it is a serious deal to learn this stuff and putting it down in writing is a tremendous help.

Oh yeah! Check this puppy out -- This is one of the new toys that appeared in class today. No, silly Trekker weenies - it is not a 1:100 scale model of the Borg², 'tis a mammoth router/switch combo called the Cisco Catalyst 4000 series³ (dig the ridiculous pose intended to make an inanimate cube look enticing). It does this fancy thing by combining both switching and routing - it takes the ARP entries it receives from the level two transmissions (through the switch) and automagically binds them to the routes in the routing table, thereby increasing throughput tremendously. I can attest to the mass of these things - I am not a small man, and I about lost it trying to pick it up.

I sure hope we get to fool with these things soon. ◊

• ¹ This clip was pilfered from moviesoundscentral.com.
• ² Image used senza permesso... thanks to www.darksim.com.
• ³ Cisco 400 Series image courtesy of some belgian feller @ www.jeb.be/