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container.training/docs/ipsec.md
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class: ipsec
# Securing overlay networks
- By default, overlay networks are using plain VXLAN encapsulation
(~Ethernet over UDP, using SwarmKit's control plane for ARP resolution)
- Encryption can be enabled on a per-network basis
(It will use IPSEC encryption provided by the kernel, leveraging hardware acceleration)
- This is only for the `overlay` driver
(Other drivers/plugins will use different mechanisms)
---
class: ipsec
## Creating two networks: encrypted and not
- Let's create two networks for testing purposes
.exercise[
- Create an "insecure" network:
```bash
docker network create insecure --driver overlay --attachable
```
- Create a "secure" network:
```bash
docker network create secure --opt encrypted --driver overlay --attachable
```
]
.warning[Make sure that you don't typo that option; errors are silently ignored!]
---
class: ipsec
## Deploying a web server sitting on both networks
- Let's use good old NGINX
- We will attach it to both networks
- We will use a placement constraint to make sure that it is on a different node
.exercise[
- Create a web server running somewhere else:
```bash
docker service create --name web \
--network secure --network insecure \
--constraint node.hostname!=node1 \
nginx
```
]
---
class: ipsec
## Sniff HTTP traffic
- We will use `ngrep`, which allows to grep for network traffic
- We will run it in a container, using host networking to access the host's interfaces
.exercise[
- Sniff network traffic and display all packets containing "HTTP":
```bash
docker run --net host nicolaka/netshoot ngrep -tpd eth0 HTTP
```
]
--
class: ipsec
Seeing tons of HTTP request? Shutdown your DockerCoins workers:
```bash
docker service update dockercoins_worker --replicas=0
```
---
class: ipsec
## Check that we are, indeed, sniffing traffic
- Let's see if we can intercept our traffic with Google!
.exercise[
- Open a new terminal
- Issue an HTTP request to Google (or anything you like):
```bash
curl google.com
```
]
The ngrep container will display one `#` per packet traversing the network interface.
When you do the `curl`, you should see the HTTP request in clear text in the output.
---
class: ipsec, extra-details
## If you are using Play-With-Docker, Vagrant, etc.
- You will probably have *two* network interfaces
- One interface will be used for outbound traffic (to Google)
- The other one will be used for internode traffic
- You might have to adapt/relaunch the `ngrep` command to specify the right one!
---
class: ipsec
## Try to sniff traffic across overlay networks
- We will run `curl web` through both secure and insecure networks
.exercise[
- Access the web server through the insecure network:
```bash
docker run --rm --net insecure nicolaka/netshoot curl web
```
- Now do the same through the secure network:
```bash
docker run --rm --net secure nicolaka/netshoot curl web
```
]
When you run the first command, you will see HTTP fragments.
<br/>
However, when you run the second one, only `#` will show up.