222 lines
7.8 KiB
HTML
222 lines
7.8 KiB
HTML
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<title>SysAdmin2022</title>
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<div class="reveal">
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<div class="slides">
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<section>
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<h2>Learning about slightly more advanced networking with linux</h2>
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<p><b>Paul Warren</b></p>
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<p>Mastodon: @pwarren@mastodon.thewarrens.name </p>
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<p>email: paul at thewarrens.name </p>
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<p>© 2021 Paul Warren</p>
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<p>CC BY-NC-SA<p>
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</section>
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<section><h2 style="color:red">! WARNING !</h2>
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<p>I am not a network engineer, there are gaps in my knowledge</p>
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<p>The words I use might not be the correct ones</p>
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<p>Please don't blame me if your network stops networking</p>
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<p class="fragment">Maybe don't go and try building an ISP based off this talk :)</p>
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</section>
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<section><h2>What even is a network</h2>
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<p class="fragment fade-in-then-out">Ethernet?</p>
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<p class="fragment fade-in-then-out">Token Ring?</p>
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<p class="fragment fade-in-then-out">IPX?</p>
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<p class="fragment fade-in-then-out">AX.25?</p>
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</section>
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<section><h2>What even is a network</h2>
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<p class="fragment fade-in-then-out">ipv4?</p>
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<p class="fragment fade-in-then-out">ipv6?</p>
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<p class="fragment fade-in-then-out">tcp?</p>
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<p class="fragment">Allows connections between computers</p>
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<aside class="notes">
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<p>We are going to mostly focus on Ethernet and IPv6</p>
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</section>
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<section><h2>Managed network?</h2>
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<p class="fragment"><b>Controls</b> connections between computers</p>
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<p class="fragment"><b>Scales</b> connections between computers</p>
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<p class="fragment"><img src="3tier.png" /><p>
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<aside class="notes">
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<p>Most of us probably work in a managed network</p>
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<p>Most of us probably have a pretty flat edge network at home</p>
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<p>Diagram is nice, but hides complexities at each layer.<p>
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</aside>
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</section>
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<section><h2>Layers!</h2>
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<p class="fragment">Like an onion!</p>
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<p class="fragment">That 7 layer thing from the OSI</p>
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<p class="fragment">Ethernet -> IP -> ICMP/TCP/UDP</p>
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<p class="fragment">Administrative overlays</p>
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<p class="fragment">VPNs and Tunnels</p>
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<aside class="notes">
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<p>or a parfait</p>
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<p>which you can mostly ignore, as what we generally use doesn't conform to it. But it does provide a good framework for assisting understanding</p>
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<p>Like firewalls, web-proxies/SSL MITM, But also access rights etc</p>
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</section>
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<section><h2>Layers!</h2>
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<p>This means the Physical layers do not have to match the Logical connections</p>
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<p class="fragment">Networks are also a bit fractal in nature</p>
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<p class="fragment">For the purposes of this talk, we can ignore a lot of complexity</p>
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</section>
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<section><h2>An easy one!</h2>
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<p>VLANS</p>
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<p class="fragment">Ethernet layer</p>
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<p class="fragment">Designed to limit broadcast storms</p>
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<p class="fragment">Can also separate IP networks on the same Ethernet</p>
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<p class="fragment">Tagged and Untagged or Default</p>
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<aside class="notes">
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<p>beware of strange implementations, windows seems to take Router Advertisements from all vlans, regardless of tag</p>
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</section>
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<section><h2>VLANs in linux</h2>
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<p>Are pretty easy!</p>
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<pre class="fragment"><code data-trim data-noescape>
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ip link add link enp0s2 name enp0s2.2501 vlan id 2501
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ip -6 addr add 2001:db8:2501::10/64 dev enp0s2.2501
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ip link set dev enp0s2.2501 up
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</pre>
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</section>
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<section><h2>VLANs in linux</h2>
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<p>Various different methods of making it go in different distributions</p>
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<pre class="fragment"><code data-trim data-noescape>
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<section><h2>What even is a router?</h2>
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<p class="fragment">Two or more interfaces</p>
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<p class="fragment">Some logic to determine where a packet goes</p>
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<aside class="notes">
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<p>Not necessarily physical</p>
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<p>Sounds simple right?</p>
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</section>
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<section><h2>Linux Routing</h2>
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<pre class="fragment"><code data-trim data-noescape>
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net.ipv4.ip_forward = 1
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net.ipv6.conf.all.forwarding = 1
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net.ipv6.conf.default.forwarding = 1
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</code>
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</pre>
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<p class="fragment">And we're done!</p>
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<p class="fragment">Yeah, not really :)</p>
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</section>
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<section><h2>Static Routes!</h2>
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<p>Manually added, or scripted routes that don't change</p>
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<pre><code data-trim data-noescape>
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ip route add 172.17.0.0/24 via 172.16.0.254 dev wg0
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</code>
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</pre>
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</section>
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<section><h2>What I'm assuming we're familiar with</h2>
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<p>Diagram showing standard leaf node of a network with a bit cloud containg "The rest of the org"</p>
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</section>
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<section><h2>What we're familiar with</h2>
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<p>Diagram showing added storage and server network<p>
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</section>
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<section><h2>How things evolve</h2>
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<p>Uh Oh, we've got a new Datacentre</p>
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</section>
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<section><h2>How things evolve</h2>
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<p>which has its own lot of storage and servers</p>
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</section>
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<section><h2>How things evolve</h2>
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<p>And now people want to work in Tasmania!</p>
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</section>
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<section><h2>Dynamic Routing</h2>
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<p>Open Shortest Path First (OSPF)</p>
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<p>The algorithm is pretty interesting</p>
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<p class="fragment">RFC2328</p>
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<p class="fragment">RFC5340</p>
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</section>
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<section><h2>Dynamic Routing</h2>
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<p>Border Gateway Protocol (BGP)</p>
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<p class="fragment">RF4271</p>
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</section>
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<section>more detail on what VLANs, OSPF and BGP are for</section>
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<section>how to do these things in linux</section>
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<section>intro to bird</section>
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<section>more detail on bird</section>
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<section>building out a virtual network with LXC</section>
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<section>ergh, NAT</section>
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<section>Why use a 'real' router</section>
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<section>OpenWRT</section>
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<section>Multi Host IPs (Authoritative DNS example like in the facebook thing)</section>
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<section><h2>Bonus homework</h2>
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<p>Why did I use 2001::db8::/32?</p>
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<p>Why did I use /64s?</p>
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<p>something ansible?</p>
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<p>DSA is relatively new, nicer way if interacting with actual switch hardware</p>
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</section>
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<section><h2>Resources</h2>
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<p>These slides: <a href="https://gitea.pwarren.id.au/pwarren/SysAdmin2022">https://gitea.pwarren.id.au/pwarren/SysAdmin2022</a></p>
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<p>bird: <a href="https://bird.network.cz/">https://bird.network.cz</a></p>
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<p>KNorrie's network examples: <a href="https://github.com/knorrie/network-examples">https://github.com/knorrie/network-examples</a></p>
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<p>Openwrt: <a href="https://openwrt.org">https://openwrt.org/</a></p>
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<p>The OpenWRT IRC channel, currently on the OFTC network</p>
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<p>BenEater's <a href="https://www.youtube.com/watch?v=-wMU8vmfaYo">"Why was facebook down for five hours" </a>
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</p>
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</section>
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</div>
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