Mr. Jetson teaches network technology



  • No, not THAT Jetson, it's just me obfuscating the author's name. So, I changed my line of work some time ago. I was aiming to become a developer, but as life thought I wasn't done with school I ended up back there. Although this time, as a teacher. At the moment with a focus teaching what the swedish school administration calls network technology, which is a set of courses about computer networks and server administration.

    Well, being new in the teacher role I thought that maybe there was some schoolbooks in my subject that I could use. And yes, there were books at my school. Now, seeing as this topic has ended up in the Sidebar you can figure where this is going. (Hint: I'm not really using the books at all.)

    Enter Mr. Jetson. Teacher/author/publisher of schoolbooks. Let us bow to his wisdom in the ways of computers and computer networks as I read from the books, starting with the base course of the network set. I shall be reading from the 2012 edition of the book.

    So, let's dig into Network Technology with Windows Server 2008 and I shall post some choice nuggets of wisdom for you all.

    This book is written based off the most used network operating system, Windows Server 2008.

    Internet is really just a single massive, gigantic and world-encompassing network.

    Between the internet and the local network a firewall is placed. This is mainly a router, whose task is to create a connection between the network address (IP-address) on the internet and the local address.

    An example of a commonly used protocol [on the network] is TCP/IP.

    To connect your own network directly to the internet you need to apply with InterNIC to be granted one or several IP addresses.

    IP addresses are divided into three different classes: Class A, Class B and Class C.

    [A DNS server] is a must if the computer shall be able to access the internet and if it is going to be able to communicate with a server on the local network.

    On a server a version of Windows Server is most commonly installed, preferrably the 64-bit edition. Also Linux is common on some types of servers.

    [FAT16] allows dual boot, that is having several operating systems installed like DOS, Microsoft NT/2000 and Windows 2003 installed on the same partition or separate drives.

    The start button Start is the most important button in Windows. This button opens the Start menu in which you can access all programs and files you have on your computer.



  • @atazhaia said in Mr. Jetson teaches network technology:

    This book is written based off the most used network operating system, Windows Server 2008.

    Probably not correct. (Well, that the book is "written based off" is correct; that Windows Server 2008 was the most-used network operating system in 2012 is probably not correct.)

    @atazhaia said in Mr. Jetson teaches network technology:

    Internet is really just a single massive, gigantic and world-encompassing network.

    Correct. Also redundant.

    @atazhaia said in Mr. Jetson teaches network technology:

    Between the internet and the local network a firewall is placed. This is mainly a router, whose task is to create a connection between the network address (IP-address) on the internet and the local address.

    Confused but generally correct. (Assuming he means "a firewall is placed" as a prescriptive statement.) For some reason it does not mention the most important keyword for this type of network, "NAT".

    @atazhaia said in Mr. Jetson teaches network technology:

    An example of a commonly used protocol [on the network] is TCP/IP.

    Correct.

    @atazhaia said in Mr. Jetson teaches network technology:

    To connect your own network directly to the internet you need to apply with InterNIC to be granted one or several IP addresses.

    Correct, but incomplete-- strangely omits that you can just rent an IP address from someone else who has one. (I'm assuming in 2012, IPv6 wasn't popular enough to be worth talking about.)

    @atazhaia said in Mr. Jetson teaches network technology:

    [A DNS server] is a must if the computer shall be able to access the internet and if it is going to be able to communicate with a server on the local network.

    Generally correct but confused.

    @atazhaia said in Mr. Jetson teaches network technology:

    On a server a version of Windows Server is most commonly installed, preferrably the 64-bit edition. Also Linux is common on some types of servers.

    Generally correct.

    @atazhaia said in Mr. Jetson teaches network technology:

    [FAT16] allows dual boot, that is having several operating systems installed like DOS, Microsoft NT/2000 and Windows 2003 installed on the same partition or separate drives.

    This is the first one I've seen that is, AFAICT, completely wrong and misleading.

    @atazhaia said in Mr. Jetson teaches network technology:

    The start button Start is the most important button in Windows. This button opens the Start menu in which you can access all programs and files you have on your computer.

    Correct, but why is it in a book about networking?



  • @atazhaia Reminds me of my IT education in elementary school. After a year of basic programming and 3D modelling we got a new teacher. His first assignment instructed us to "open the 'My Documents' program."



  • @blakeyrat This first book mainly had confusing quotes. Although some things I do define as wrong.

    • Windows Server is not the most used network OS.
    • TCP/IP is not a protocol, it's a collection of protocols.
    • I've never applied to InterNIC to get an IP, I just get that from my local ISP. Also, asking InterNIC for IP addresses in 2012 would be a bit difficult, seeing as that organisation closed down in 1998.
    • A DNS server is not a requirement for internet connection or communication on a network, although it does help a lot.

    The name of the course is a bit misleading, as it focuses on basic server administration. The set of courses is part servers, part networks and network equipment.


  • Winner of the 2016 Presidential Election

    @blakeyrat yeah, that's pretty much my thought too. Most of it is right, uh, kinda, I guess. But it's like the quotes are all entirely missing the point of actually teaching networking.



  • @AtazhaiaMr. Jetson said in Mr. Jetson teaches network technology:

    Internet is really just a single massive, gigantic and world-encompassing network.

    It's pretty impressive when someone can write a sentence and not know what the first word in that sentence is.

    @AtazhaiaMr. Jetson said in Mr. Jetson teaches network technology:

    IP addresses are divided into three different classes: Class A, Class B and Class C.

    As dumb as that sounds, it was probably true when the book was written.



  • @atazhaia said in Mr. Jetson teaches network technology:

    TCP/IP is not a protocol, it's a collection of protocols.

    TCP over IP is a protocol in the same way that HTTPS is a protocol.

    Combining protocols gives you a protocol, just like combining functions gives you a function.



  • @deadfast said in Mr. Jetson teaches network technology:

    @atazhaia Reminds me of my IT education in elementary school. After a year of basic programming and 3D modelling we got a new teacher. His first assignment instructed us to "open the 'My Documents' program."

    I had a Java teacher in high school who needed my help when another student wrote something along the lines of if (foo) && (bar) and neither of them could figure it out even though the IDE (I think it was an ancient-at-the-time version of Eclipse) had a big red squiggly underline saying exactly what was wrong.

    That class also included a lot of tests where you had to "solve" a Java program with inconsistent formatting without the use of a computer. I think a few times I pointed out to the teacher that the correct answer wasn't included in the multiple choice, or that the program couldn't possibly have any output because it had a syntax error (in at least one case it was so badly formatted that I couldn't figure out where in the program the missing punctuation mark was supposed to be).


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    @ben_lubar My Java teacher in high school, when I asked him why a particular line could be throwing a NullPointerException, told me he had no idea and maybe I should Google NullPointerException because he'd never heard of it.
    This was the same guy who told us 'debugging' was removing the syntax errors from the code.



  • @pie_flavor said in Mr. Jetson teaches network technology:

    This was the same guy who told us 'debugging' was removing the syntax errors from the code.

    If your code has syntax errors, good luck running it in a debugger.

    Except JavaScript, I guess.



  • @atazhaia said in Mr. Jetson teaches network technology:

    TCP/IP is not a protocol, it's a collection of protocols.

    Not true. TCP/IP is certainly a protocol. It's a layer 4/5 protocol, but those are still protocols.

    @atazhaia said in Mr. Jetson teaches network technology:

    I've never applied to InterNIC to get an IP, I just get that from my local ISP. Also, asking InterNIC for IP addresses in 2012 would be a bit difficult, seeing as that organisation closed down in 1998.

    Ok the out-of-date point is well-founded, but the book isn't entirely wrong.

    @atazhaia said in Mr. Jetson teaches network technology:

    A DNS server is not a requirement for internet connection or communication on a network, although it does help a lot.

    This is pedantic dickweedery. For people who aren't pedantic dickweeds, a DNS server is required to use the internet.


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    @blakeyrat said in Mr. Jetson teaches network technology:

    a DNS server is required to use the internet.

    False. You could just put in IP addresses (the only one you really need is Google's), or make a hosts file.



  • This is pedantic dickweedery. For people who aren't pedantic dickweeds, a DNS server is required to use the internet.

    Don't be a pedantic dickweed.



  • @blakeyrat said in Mr. Jetson teaches network technology:

    This is pedantic dickweedery. For people who aren't pedantic dickweeds, a DNS server is required to use the internet.

    Don't be a pedantic dickweed.

    Except that the sentence also says that a DNS server is a requirement for a local network, which is completely untrue. I've never once connected to a machine on my network using the hostname unknownc821586eb829.attlocal.net instead of its static IP address.


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    @blakeyrat For people who aren't pedantic dickweeds, Java == JavaScript.
    For people who aren't pedantic dickweeds, hacking is done by typing fast for about a minute.
    For people who aren't pedantic dickweeds, error messages are always generally incomprehensible and no effort should be taken to read them.
    For people who aren't pedantic dickweeds, knowing HTML counts as being a web developer.
    For people who aren't pedantic dickweeds, string concatenation is a perfectly acceptable way to construct SQL statements with user-inputted values.



  • @pie_flavor said in Mr. Jetson teaches network technology:

    For people who aren't pedantic dickweeds, string concatenation is a perfectly acceptable way to construct SQL statements with user-inputted values.

    Real error message on my build server:

    An error occurred in the web application: Release 0.44.02-alpha1" or (1,2)=(select*from(select name_const(CHAR(111,108,111,108,111,115,104,101,114),1),name_const(CHAR(111,108,111,108,111,115,104,101,114),1))a) -- "x"="x does not exist.
    

    I'm not sure what database they were trying to do SQL injection into, but it's a server that uses double quotes for strings, which narrows it down to zero databases I have ever used.



  • @blakeyrat said in Mr. Jetson teaches network technology:

    Don't be a pedantic dickweed.

    I think you might be on the wrong website.



  • @blakeyrat said in Mr. Jetson teaches network technology:

    Ok the out-of-date point is well-founded, but the book isn't entirely wrong.

    No, it's not entirely wrong, but it is woefully inaccurate in preparing the students to deal with actual real-life situations. In a job situation there really isn't that much of a difference between "I don't know" and "technically correct but completely inapplicable".



  • @ben_lubar said in Mr. Jetson teaches network technology:

    it's a server that uses double quotes for strings, which narrows it down to zero databases I have ever used.

    Meet MySQL and SQLite.



  • @dcoder said in Mr. Jetson teaches network technology:

    @ben_lubar said in Mr. Jetson teaches network technology:

    it's a server that uses double quotes for strings, which narrows it down to zero databases I have ever used.

    Meet MySQL and SQLite.

    SQLite does not use double quotes for strings. A release number would not be stored as a column name. And I've never seen MySQL used with double-quoted strings, so I'm pretty sure there's no popular software that would be vulnerable to that attack.



  • @ben_lubar
    The SQLite documentation I linked says:

    If a keyword in double quotes (ex: "key" or "glob") is used in a context where it cannot be resolved to an identifier but where a string literal is allowed, then the token is understood to be a string literal instead of an identifier.



  • @pie_flavor said in Mr. Jetson teaches network technology:

    @blakeyrat said in Mr. Jetson teaches network technology:

    a DNS server is required to use the internet.

    False. You could just put in IP addresses (the only one you really need is Google's)

    1. Most websites (especially those on shared hosting) don't work with IP alone - you actually need to use domain name to connect.
    2. Google isn't enough - the results all use domain names, so you need DNS for them (or hosts file entries, but at this point you'll making your own DNS cache basically).


  • If everyone had to type in IP addresses, I'm pretty damn certain the internet would be nowhere near as popular as it is.

    @pie_flavor I dare you to code something only typing in alt codes. It hypothetically can be done, so it's perfectly cromulent to do so, right?


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    @gąska You would just google for their IP addresses.


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    @coderpatsy Sounds like a good idea for APL, I just have to keep a sheet on hand



  • @pie_flavor said in Mr. Jetson teaches network technology:

    @gąska You would just google for their IP addresses.

    Even then, you'd have to put it in hosts file. Or otherwise make a request to that IP that includes domain name.

    Also, I'm pretty sure Google search can't tell you IPs, so rather than Google's, you'd have to remember IPs of one of such IP lookup websites.

    The point is. Internet without DNS is mostly unusable, and to make it usable you need to manually duplicate DNS functionality.


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    @gąska said in Mr. Jetson teaches network technology:

    Also, I'm pretty sure Google search can't tell you IPs, so rather than Google's, you'd have to remember IPs of one of such IP lookup websites.

    Ah, my bad. So then all you'd need is one of them (156.154.208.10).



  • @pie_flavor and hope it doesn't change.

    Also, I wonder how your little scheme would play with load balancers and other redirect scenarios.


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    @gąska Ah, but that's not part of the Internet, is it? Blakey didn't say anything about the World Wide Web.



  • @pie_flavor I'm pretty sure that the difference between WWW and Internet is the same as between an object and an instance in OOP.


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    @gąska The Internet is the interconnected network of computers that talk to each other. The World Wide Web is a system of providing documents which link to other documents. Basically TCP/IP vs HTTP/HTML.



  • @pie_flavor OK, so the difference is more clearly defined (although an FTP server full of PDFs also fits the definition despite not using either HTTP or HTML).

    Anyway, the point is... you must be a masochist if you don't use DNS.


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    @gąska said in Mr. Jetson teaches network technology:

    Anyway, the point is... you must be a masochist if you don't use DNS.

    And I don't doubt that @blakeyrat is. So 🤷


  • Discourse touched me in a no-no place

    @ben_lubar said in Mr. Jetson teaches network technology:

    it's a server that uses double quotes for strings

    That's properly wrong (they're really supposed to be the kind of quotes around identifiers that you use when you've got a name that would otherwise be illegal), but are often accepted anyway. Probably because of MySQL; that's been the PHP of databases for a long time, and the other engines put up with it because that's the path of least resistance overall…



  • @pie_flavor it's not him who insists that Internet is at all usable without DNS.


  • Discourse touched me in a no-no place

    @gąska said in Mr. Jetson teaches network technology:

    you'd have to remember IPs of one of such IP lookup websites

    8.8.8.8

    Easy, yes? (It happens to use this protocol called DNS for communication, but that's a detail.)


  • Discourse touched me in a no-no place

    @gąska said in Mr. Jetson teaches network technology:

    an FTP server full of PDFs also fits the definition

    Reminds me of gopher and wais. Not in a good way either.



  • @dkf said in Mr. Jetson teaches network technology:

    @gąska said in Mr. Jetson teaches network technology:

    you'd have to remember IPs of one of such IP lookup websites

    8.8.8.8

    I said, websites.



  • @pie_flavor said in Mr. Jetson teaches network technology:

    @gąska You would just google for their IP addresses.

    Better yet: someone could publish a big book in which you look up their name and address, and learn the IP address.



  • @gąska said in Mr. Jetson teaches network technology:

    Also, I'm pretty sure Google search can't tell you IPs

    Didn’t it used to, though? ISTR (but could be wrong) that it used to show IP addresses below the name of the site.


  • Discourse touched me in a no-no place

    @ben_lubar said in Mr. Jetson teaches network technology:

    Except that the sentence also says that a DNS server is a requirement for a local network, which is completely untrue. I've never once connected to a machine on my network using the hostname unknownc821586eb829.attlocal.net instead of its static IP address.

    On a local network, you can use a hosts file or a broadcast autodiscovery protocol. Neither scale; the former requires much futzing around by admins as the list grows (despite working fine for a small number of devices), and broadcast discovery protocols have the nasty habit of gradually increasing to consume ever larger fractions of total bandwidth as the network grows (which is why they're typically blocked from crossing gateway routers). So instead we use a name service somewhere that specialises in knowing the mapping of “friendly” names to machine-routable addresses; these typically speak DNS these days because that actually can scale up to the whole world's internet (DNS was the original killer app of the internet).

    Of course, there's other things going on as well (e.g., DHCP for finding the DNS service in the first place, ARP for the low-level routing info, BGP for large scale routing management, etc.) but DNS is the core.


  • Fake News

    @ben_lubar said in Mr. Jetson teaches network technology:

    @AtazhaiaMr. Jetson said in Mr. Jetson teaches network technology:

    IP addresses are divided into three different classes: Class A, Class B and Class C.

    As dumb as that sounds, it was probably true when the book was written.

    Seeing how CIDR was introduced in 1993, the book had something short of 19 years to get updated for its 2012 edition.

    Maybe the author was too busy raising kids?



  • @ben_lubar said in Mr. Jetson teaches network technology:

    As dumb as that sounds, it was probably true when the book was written.

    I can mention that this block of courses were introduced with the 2011 course plan (the current one in use) as far as I can tell, meaning he doesn't have the defense of having the first edition written in the 80s. I am doing an advanced guess and saying that this is the first edition of this book.



  • Let's check the next book: Networking Technologies (2013 edition) which handles how communication works in computer networks.

    There are two types of modulation, Amplitude Modulation (AM) and Frequency Modulation (FM). ... Nowadays FM is used almost exclusively. This is especially true for data traffic.

    ...ADSL where you can send data with up to 60Mbit/s (jan 2012) on an ordinary phone line.

    Maybe a bit pedantic when I point out that it's VDSL at those speeds as ADSL only goes up to 24 Mbit/s. Although he's wrong on the maximum speed anyway, as VDSL back then had a maximum speed of ~100Mbit/s.

    ...but USB 2.0 which is standard today is several times faster than FireWire

    We shall now take a look at the two most common topologies, Ethernet and Token Ring.

    UDP is a simpler form of TCP.

    POP3 is the most common protocol for receiving e-mail over the internet.

    Supernetting, CIDR
    Supernetting is a version of subnetting. Instead of splitting a network into several smaller subnets you can merge several networks into a larger network. ... Supernetting is created by shortening the subnet mask and "borrowing" parts of the Net-ID to a new Computer-ID. ... The tech for making this is also called CIDR, Classless Inter-Domain Routing. To use this in a network all routers must support this functionality. [Insert table showing supernetiing of class C networks.]



  • @ben_lubar said in Mr. Jetson teaches network technology:

    As dumb as that sounds, it was probably true when the book was written.

    Nah, it was wrong even then. Class D (multicast) and Class E (experimental services) got left out.



  • @pie_flavor said in Mr. Jetson teaches network technology:

    @gąska said in Mr. Jetson teaches network technology:

    Also, I'm pretty sure Google search can't tell you IPs, so rather than Google's, you'd have to remember IPs of one of such IP lookup websites.

    Ah, my bad. So then all you'd need is one of them (156.154.208.10).

    Oh, another thing. SSL certificates are pinned to domain names, so when accessing websites by IP instead, you'll get endless stream of those annoying insecure connection errors. I completely forgot about that, but trying to visit the address in your post auickly reminded me.


  • Discourse touched me in a no-no place

    @gąska said in Mr. Jetson teaches network technology:

    SSL certificates are pinned to domain names, so when accessing websites by IP instead, you'll get endless stream of those annoying insecure connection errors.

    They could be pinned to the IP address, but that's less useful. Pinning to something recognisable by (OK, smarter than average) users works far better.


  • Fake News

    @gąska You likely need to add the site to your hosts file anyway as any reverse proxy on the site's web hosting will require the browser to send a Host: header to target the right virtual host.


  • Grade A Premium Asshole

    Mr. Jetson teaches family budgeting and negotiation:

    Family Guy ● The Jetsons – 00:44
    — A Update


  • Discourse touched me in a no-no place

    @gąska It is usable without DNS. Just not very well.


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