light geekery

[arethinn]

I'm considering applying for this computer support position with Central Services (third entity in the district, serves both campuses, hence the name): http://fhdafiles.fhda.edu/downloads/employment/07097.pdf

Although my resume doesn't include any other jobs similarly titled, I've had to do a lot of troubleshooting in the Media Lab, and even working in Technical Services I was often asked by co-worker and even supervisor to try to fix something on one of their machines. Judy has also used me to install various software to all the staff computers (it has not always been the case that we had a dedicated technician, and anyway in the case of Sirsi, it's easier to have someone who uses the software daily and understands what should be happening do the upgrades, rather than someone who barely touches the thing), mess around with the Java version of the client to see how bad it was before transitioning to it (it's so bad we still haven't done it. ha. but that was the case of the Sirsi tech support guy itself agreeing with my assessment of what was causing one particular problem, and assuring us they'd put a fix into the next patch for the client. go me.), etc etc. There was even one ETS guy who gave me passwords he probably shouldn't have done so that I could fix certain problems that required logging in as an administrator, because he knew I knew what to do and what not to do (I probably shouldn't mention that in a cover letter tho!). And of course there's the fact that we've been building up computers from scratch in my house since I was in high school.

I don't have all that much experience with Mac OS X, but I can fake it. The Macs here in the Media Lab have that so I have at least reasonable familiarity with it. The only thing I am really in the dark on is TCP/IP configuration and troubleshooting. I have almost zilch experience with that. I have never set up an intranet, for example. Getting the MetroFi wireless to work at my house has been somewhat instructive, but since the nature of Windows is to obscure what is really going on from the end-user, I don't really know anything except "clicky here to try to produce this result". I have no insight into the Network Nature.

So, the moral of this story is: Does anyone have any recommendations for a crash course in TCP/IP? I do not need deep esoteric knowledge - this is a support technician, not the Senior Network and Systems Programmer. But I should at least have a clue what all the terms mean (wtf ARE "subnet mask" and "default gateway", anyway? I have never grokked this, despite previous explanations), be able to diagnose problems from given symptoms, and know what actions to therefore attempt in various situations.

Comments

[michiexile]

Default gateway and Subnet mask are coupled: when your computer wants to talk with Someone Else, that someone else either is Really Close or Outside My Neighbourhood.

If it's Really Close, then that means that if you just look at the bits of the IP address of Someone Else that coincide with the set bits of the subnet mask, then that should be the same as if you were to do the same with your own IP. Checking these bits is Really Easy (tm) in programming: it consists of a bitwise and, (which is the operator &, or something very similar in most languages)

If it's not Really Close, then your computer doesn't know what to do with the data. In that case, it starts looking through an internally stored table, that gives various IP ranges, and where to find those. The table also has a Default gateway designated: this means that if you can't figure out what to do with the data, you just send it to your Default Gateway, and make it his problem.

He, on the other hand, tends to know much better than you what to actually do with the data, due to someone else telling him where to send it.

[rhiannasilel.livejournal.com]

This site has a really basic overview. I saw a few other ones that looked pretty decent on a google search. You may also want to check out a study guide for the Network + exam, which you can sometimes find fairly cheaply, especially if you get one that's deprecated.

[rainsingingwolf.livejournal.com]

Net+, like Rhiannasilel said, is what you need for the basic.

[starlightforest.livejournal.com]

I totally didn't understand a word you just said. Try not trying to turn it into Plain English, maybe (no, really).

[starlightforest.livejournal.com]

Thanks, I'll have a look.

[starlightforest.livejournal.com]

"Really basic" is right. Didn't tell me anything I didn't already know aside from expanding the acronyms for me. What "looked pretty decent" on Google? I figured if I Googled for "TCP/IP course" or something I would get too many results to be useful, which is why I was asking for recs.

[rhiannasilel.livejournal.com]

Ah, okay, wasn't quite sure what level you were looking for. You may want to try these:

Not great, but okay:
http://compnetworking.about.com/od/workingwithipaddresses/l/blip.htm

This looks decent at a quick glance:
http://www.comptechdoc.org/independent/networking/guide/index.html

If you follow the various links through this one, it looks decent and even has an IPv6 tutorial on it, although it's more likely than not that you'd probably have to deal with IPv4:
http://www.pcsupportadvisor.com/TCP_IP_tutorial_page1.htm

There's a bunch of stuff here:
http://www.techtutorials.info/nettcpip.html

Hope this helps. You may also want to check out one of the Network + books, which you may even be able to find at your local library. Since you're not using it to study for the actual exam, it won't really matter all that much if it's a little out of date.

[windtree.livejournal.com]

subnet - the part of the IP address range that makes up your local area network. Subnets are usually written as either IP addresses (11.22.33.00) or ip blocks (11.22.33/8) where the /N part indicates how many bits are being used for the subnet.

subnet mask - the part of the IP address that would block out addresses not on your subnet. So if your subnet is 11.22.33.00 (ie. all machines between 11.22.33.01 and 11.22.33.FF) then the subnet mask is FF.FF.FF.00 (or 255.255.255.0 in decimal).

default gateway - the IP address to send packets to for addresses that aren't on your subnet (on the assumption it knows how to forward them onwards).

[starlightforest.livejournal.com]

Thanks. This has also been made clear to me in the two books a co-worker lent me.