How computers communicate, from the ARPANET to today's Internet

Tutorials & Resources
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41

When I click your link I get a 404. There are some trailing characters: %E2%80%9C

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42

I fixed it, try it now.

Ernie

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43

You should decide.
What you started with was a simple laymans explanation… maybe that is where the need is.

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44

I’ll have to give it some thought. The layman’s approach has some appeal to me, but I’d like a more sophisticated approach for the more advanced user too, maybe sections, titled something like Beginner or Newbie for those just starting to learn, perhaps with references to a few online tutorials in addition to what we already have in this topic, then another, titled something like Advanced for the more knowledgeable users, organized more like a reference guide.

What do you all think?

Ernie

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45

Somewhere in the back of my mind I remember hearing something about selecting a DSN. I did a quick google search on DNS and one item was titled “Best free and public DNS server of 2025”. From it’s title, it sounds like you can select the DNS you want to use.

I would like to hear your opinion on a DSN.

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46

DSN is a Data Source Name. I don’t get too deep into network support, but our AWS Direct Connect has a DSN setting that needs to match the one provided by AWS. I think of it like having a couple different WiFi networks. They’re both using the same frequency range but a different SSID.

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47

Sorry, finger check (mistake) , I will edit. I meant DNS - Domain Name System

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48

There are a few free DNS servers you can use, and AFAIK they require no sign-up. All you have to do is change the two IP addresses you’re currently using to those provided by the DNS server you want to switch to.

First, but in no specific order is Google’s Public DNS: The two IP addresses for it are 8.8.8.8 (primary) and 8.8.4.4 (alternate). Next is OpenDNS: The two IP addresses for it are 208.67.222.222 (primary) and 208.67.220.220 (alternate). Finally, I have Quad9: The two IP addresses for it are 9.9.9.9 (primary) and 149.112.112.112 (alternate).

Of the three, Quad9 and OpenDNS offer security by blocking known malware sites, and OpenDNS also has adult-content and custom filtering available (pulled directly from the Ask Leo! article). You can choose the OpenDNS server nearest to where you are from a list. I collected this information from the Ask Leo! item referenced above. I suggest you read it too, because he explains everything better than I can.

I hope this helps,

Ernie

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49

Mine are dyslexic fingers :slight_smile: I’m forever going back over anything I write to make sure my spelling’s correct …

Ernie

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50

Those public dns servers seems to be the trend today.
Originally individuals or sites ran their own dns server to resolve local lookups and as a contribution to spreading the burdern DNS placed on the internet. There was a time when you could not register a domain without providing a nameserver. You can still run your own nameserver today, if you wish. It is far easier to use your ISP’s nameserver or one of the public ones.
Hope this puts it in perspective.

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51

I think the public name servers answer the need for better security (Two of the three I listed block known malware sites), and residential users who may have a home network, but no domain name for it, just a single modem/router to protect one or more devices connected behind it.

Ernie

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52

There is also 1.1.1.1 from Cloudflare for DNS.

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53

Hi Ernie,
I did a little digging on this DSN server and it seems my connection is controlled by the ISP.
And there is a loopback (?) IP address. So 3 questions.

1 - Do you usually recommend changing the DNS and if so to which one?
2 - Would I have to make the change in the modem/router to make it permanent?
3 - Do you think it is worth changing it or just leave the default?

Thanks,
Howard

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54

Did you change you default DNS?

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55

Not in the modem, in your computer.

  • If you configure your network manually , you edit the file /ete/resolv.conf to change your nameserver
  • If you use NetworkManager ( or any other network management tool) it will configure /etc/resolv.conf for you

https://www.baeldung.com/linux/etc-resolv-conf-file

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56
  1. That’s a question you must answer for yourself Record your existing DNS addresses on a sheet of paper, just in case you want to go back, then go ahead and change the DNS addresses to test whether it makes any difference.
  2. If you can change the incoming (WAN) DNS addresses in your modem/router, the change will cover your entire home Network, while changing it on your computer will only affect your computer’s Internet connection. My ATT modem/router doesn’t have any WAN-side DNS fields in the configuration that I could find, so I had to make the changes on my computer as a test for now. I still have to do an Internet search to see if there’s a setting I missed, using my modem/router’s model name.
  3. After changing to the Quad9 DNS server, there was a noticeable difference in how fast webpages load, so I’m going to try to discover how to change it on my modem/router. I do think the difference is worth the effort, but that’s with my home Network and my ISP. Your mileage may vary

Ernie

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57

If there’s a configuration setting for the DNS servers in the modem/router, changing it there will affect the entire home network in one fell swoop, potentially avoiding the possibility that some connected devices are still using the DNS server provided by the ISP, but whether that matters depends on how much you care about your ISP having access to everything you search for, and every webpage you go to.

Ernie

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58

I did not know one could do that in the modem.
I prefer not to fiddle with my modem.
I am not sure which nameserver provider I would trust. … all they access is IP addresses resolved. Who cares about that?

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59

This is the one that went wrong about a month back and caused all sorts of problems for several hours. Down to a faulty upgrade path. Happens to them all.

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60

Most modern distros no longer have a static /etc/resolv.conf…

Network Manager will overwrite any changes you make…

And I kinda HATE that… What was wrong with that system anyway? And it was dynamic - edit that file, save it - and instant result! Now you have to jump through a bunch of hideous hoops…

So - on things like RHEL8, 9, 10, Ubuntu 16 and later… Probably Debian 13… Fedora 30.x and later…

You have to let NetworkManager manage your resolver…

You can usually still query the file - e.g. “cat /etc/resolv.conf” but it will have some guff in it about being managed by NetworkManager…

And I can’t be arsed learning nmcli commands - so I use “nmtui” - i.e. its NetworkManager’s text user interface…

Ubuntu will usually point back at itself (e.g. 127.0.0.x address)… it’s using systemd-resolvconf… I really kinda hate that…

Debian 12 will probably have something like this :

╭─x@frambo ~  
╰─➤  cat /etc/resolv.conf
# Generated by NetworkManager
nameserver 10.0.0.1
nameserver 8.8.8.8
nameserver 8.8.4.4
# NOTE: the libc resolver may not support more than 3 nameservers.
# The nameservers listed below may not be recognized.
nameserver fe80::da44:89ff:feee:c453%wlan0

So if I edit the above - it will probably get overwritten if I reboot…

Once upon a time /etc/resolv.conf was universal across most UNIX systems, and Linux and the BSD’s…

Now they’re all different - it’s fractured and broken up and none of what you know about one system (e.g. Debian) will be true on another (e.g. Red Hat)… Who asked for this anyway?

I’ve never worked with things like Token Ring… I do remember coaxial cable for mainframe terminals - 3270 or whatever it was called… No idea how it worked…

And I remember running other protocols on ethernet like netbeui - which was an ugly non-routable broadcast protocol, and also IPX/SPX, which could be routed - but it could also get very shouty and broadcast packets (like when playing Doom on a Novell Netware network)…

And running netbeui (and netbios on TCP/IP), ipx/spx and TCP/IP on hybrid media, e.g. fibre between ethernet hubs (e.g. trunks between different buildings on a campus), then UTP to other hubs, then coax ethernet - which had to be terminated at each end and the whole thing would break when someone disconnected one side of the network - so neither end was terminated - what fun!

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