diff --git a/modules/resources/exercise_networking.md b/modules/resources/exercise_networking.md index 6618b9a..c531dfd 100644 --- a/modules/resources/exercise_networking.md +++ b/modules/resources/exercise_networking.md @@ -54,24 +54,35 @@ Who gave you this second address? Can the client ping both IP addresses? Can the client now ping outside of the network? -There are **two** main things you need to do in order for the router to actually route. +The *easiest* way to achieve routing between your internal network and the outside world is to enable [NAT](https://en.wikipedia.org/wiki/Network_address_translation) on your router. +In order to do this, you need to do 2 things. +First enable the kernel to actually forward packages, secondly `iptables` needs to do masquerading. +You can do both these things with just to simple commands on you router. 1. IP forwarding needs to be setup on the router 2. NAT needs to be enabled +From here on out all your clients *should* have internet access but you won't be able to `ping` your clients from outside your network. +Your clients can ping each other and the internet at large but for clients **outside** of their mini network the router will **masquerade** the IP address. +This means that from outside your network, you'll never be able to ping a specific client, just the router itself. + ```bash sysctl net.ipv4.ip_forward=1 iptables -t nat -A POSTROUTING -j MASQUERADE ``` These settings won't save themselves so next time you reboot they'll be missing. -There are multiple ways of setting this up. -Have a look around and find me a good solution! +For the kernel option you should have a look at `/etc/sysctl.conf`. +In this file you can enable, disable or set kernel values. + +To save `iptables` rules have a look online but [this](http://www.faqs.org/docs/iptables/iptables-save.html) and [this](https://zertrin.org/projects/iptables-persistent/). ### Extra Challenge Your client machines are now behind a NAT. Can you think of a way to ssh into them? +As you can only ping the router from outside of the network you'll have to setup [port forwarding](https://en.wikipedia.org/wiki/Port_forwarding). +On Debian this is done with [iptables](https://serverfault.com/questions/532569/how-to-do-port-forwarding-redirecting-on-debian#532575). ## DHCP diff --git a/modules/resources/network_solo.dia b/modules/resources/network_solo.dia new file mode 100644 index 0000000..602f2d1 --- /dev/null +++ b/modules/resources/network_solo.dia @@ -0,0 +1,2512 @@ + + + + + + + + + + + + + #A4# + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + 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