• grandkaiser@lemmy.world
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    2 years ago

    Hi, professional DNS engineer here! if anyone has any questions about the inner workings of DNS or top level domains, ask away! (THIS IS MY MOMENT)

      • grandkaiser@lemmy.world
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        2 years ago

        Also, if you’re genuinely interested in this field, first you should enter the world of enterprise network engineering. Get Security +, CCNA, and PCNSA. With those certs in hand (and knowledge in your brain), apply to jobs as a network support engineer. Do the work for a few years. Learn BIND. Learn Infoblox. Focus on learning DHCP and subnetting. Learn DNSSEC & IPv6. Experiment with a Pi Hole. Set up a home lab. Apply to jobs with DNS. Start living the good life. This takes about 10 years if you learn fast and are good at interviews.

        • sol87@lemmy.world
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          1 year ago

          I only just now saw this post, the last month i have already been going all out to learn everything that i need for my Security+ (then CySec+) i have a 30hr video course im part way thorugh, and ive set up a few VMs with various servers like OWASP Security Shepherd and Dam Vunurable Web App for some more hands on experience as well as testing on my personal production Nextcloud and Jellyfin servers and ive been having alot of fun with it all, i think im pretty solid with DHCP and subnetting already through my home networking adventures. I will look into each of those other Certs and each thing you mention to learn thank you! Ive been deep into various Linux systems since about 2008 and im hoping to leverage that as much as i can(although its left me with a lack of modern Windows experience).

          Thank you so much for all the tips! I feel some good things coming as im getting into this as work.

      • grandkaiser@lemmy.world
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        2 years ago

        Ah, thanks for the info! I have no idea how Lemmy stuff works. I only became aware of Lemmy last month.

    • starman@programming.dev
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      2 years ago

      So, how some companies get right to sell TLDs? Can I start selling TLDs nowdays? It’s just that they were there first and get all top level domains and now we have to pay for it?

      Thanks in advance.

      • grandkaiser@lemmy.world
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        2 years ago

        Companies don’t/can’t sell TLD’s. Only IANA can decide those. When the internet first started, .org, .net, .com etc. were handed out to non-profit organizations and the costs were purely to keep the servers running. Eventually though, when IANA decided to hand out country codes like .io (Indian Ocean), .cat (Catalonia) or .tv (Tuvalu), those countries rent their “desirable” names to private organizations that sell domain registrations for lots of money. In 2013, IANA decided to enact the gTLD auctions to help raise more money. Basically, if you wanted to (and had a lot of money & DNS engineers on staff), you could register any TLD you want provided you were willing to make a large donation to IANA. If someone else wanted it, they had to go into an action war over it. That’s how we ended up with things like .party or .sport or .world cough Now-a-days, if you want a TLD, you’d have to convince IANA to give you one… But good luck with that. They won’t give you one unless you’re some major corporation that can actually handle it. They also just don’t give them out. Usually it’s only when they really feel like more TLD’s are needed. It’s a very serious responsibility and mismanagement could accidentally DDOS a DNS root zone & impact the internet.

    • jmanjones@lemmy.world
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      2 years ago

      When I was talking my cyber security / ethical hacking class, we learned how to do zone transfer. The concept never stuck and I basically “copy” from my friend. So what exactly is a DNS Zone Transfer?

      • grandkaiser@lemmy.world
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        2 years ago

        Friday I was doing a zone transfer! What are the odds?

        A zone transfer is like moving houses, except for an authoritative zone.

        In DNS, we have what’s called an authoritative zone. That means the device hosting the “resource records” (all the data that DNS passes around) is the “ultimate” answer. I.e, it’s not cached data. It’s not a hosts file. It’s not a recursive answer. It’s the real deal.

        When you want to move the authoritative zone to another server, you do a “zone transfer” that means the new server will copy all the resource records over TCP from current authoritative zone. The reason you may want to do this instead of manually hand-jamming it is that many large organizations have, sometimes, hundreds of resource records (last month I coordinated a zone transfer that was over 1000 records!).

        • jmanjones@lemmy.world
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          2 years ago

          Why would a hacker want to conduct a zone transfer? In otherwords, what is the utility or usefulness of a zone transfer for a hacker (black or white hat)?

          • grandkaiser@lemmy.world
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            2 years ago

            If you initiate a zone transfer, you can now claim to be authoritative for a zone. That means you can be a ‘bad actor’ DNS server that serves fake records. In practice, this means that you can redirect people to an attack site.

            Let’s say you’re Joe the Random Internet User and you want to go to lemmy.world This is what happens in a non-attack (we’re skipping caching & non-authoritative answers for brevity):

            1. You type “lemmy.world” into your browser
            2. Your computer initiates a stub resolution for lemmy.world. (the trailing dot here isn’t a period. It’s the “true” FQDN)
            3. Computer looks at hosts file and doesn’t see anything
            4. DNS packets are sent to your configured DNS server. If you don’t have one configured, DHCP already configured it for you
            5. Your DNS server performs a recursive search for world by asking the root zone where the “world” Name Serer is
            6. root zone resolves world as:

            world. 3600 IN NS v0n0.nic.world.

            world. 3600 IN NS v0n1.nic.world.

            world. 3600 IN NS v0n2.nic.world.

            world. 3600 IN NS v0n3.nic.world.

            world. 3600 IN NS v2n0.nic.world.

            world. 3600 IN NS v2n1.nic.world.

            1. Your DNS server reaches out to one of those Name Server’s (That’s what the NS record is for) and asks it where “lemmy” is
            2. world Name Server responds with:

            lemmy.world. 300 IN A 172.67.218.212

            lemmy.world. 300 IN A 104.21.53.208

            1. Your DNS server contacts your computer and serves it those IP addresses. (A record’s are domain name to IP Address)

            Now lets say there’s a DNS spoof attack:

            1. Before the “world” server can get back to your DNS server, the hackers server interjects with it’s own authoritative claim that lemmy is here:

            lemmy.world. 300 IN A [attack site IP]

            1. Your DNS server contacts your computer and serves it that IP address. Your computer then contacts the attack site and you get a virus.
    • lazylion_ca@lemmy.ca
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      2 years ago
      1. Could users set a temporary entry in their hosts file pointing the .ml domains to public IPs in order to regain access to their account if they needed to?

      2. Can Lemmy federate to an IP address directly or will the settings only accept an fqdn?

      3. Will a Lemmy instance work behind a reverse proxy.

      Thanks for taking the time to answer questions.

      • grandkaiser@lemmy.world
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        2 years ago
        1. Yes. Unless there’s some kind of crazy domain-level hi-jinks involved with Lemmy (I am not versed in Lemmy), pointing directly to the IP will work if you bypass it by spoofing your DNS (Hosts file, for example).
        2. I don’t know how Lemmy federation works, sorry :(
        3. See #2

        Sorry that I couldn’t answer more of your questions.

      • sol87@lemmy.world
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        2 years ago

        There are several problem with this including total lack of SSL without the proper cert for that other domain, also Lemmy.ml’s IP seems to be running a reverse proxy so the internal IP that we would want to connect to is not visible to the world this is common for web security, the owners must set allowed domains and ports in their config file.

        If none of that was a problem Lemmy itself does not do well with changing domains, as highlighted here: https://lemmy.nrd.li/comment/190200