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Flesh out First attempt

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I still need to document the DHCP bits.
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Reynir Björnsson 2020-11-09 09:25:14 +01:00
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@ -42,3 +42,18 @@ Then I made a `.network` file with a `[Match]` clause matching on names starting
Finally, I configured an address on the bridge so we can communicate with the VMs from the host.
This seemed to work, but the unikernel I was testing with, [Canopy](https://github.com/Engil/Canopy), fetches data from an online git repository.
Since I hadn't done anything to give it access to the internet it of course failed and crashed.
### Getting Canopy on the internet
I found the options `IPForward=true` and `IPMasquerade=true` on the bridge did the trick.
One thing to note is `IPForward=true` and `IPForward=ipv4` sets globally the sysctl option `net.ipv4.ip_forward`, and never unsets it.
The systemd documentation says to use a firewall to work around this.
The option says to the kernel to route packets across interfaces.
The option `IPMasquerade` basically enables NAT so the packets to the internet coming from the VM will look like they come from the host.
### Using DHCP
So far I had been using statically configured addresses and routes.
I got it working to some degree.
Canopy seems to work fine with the ISPs DNS servers, but less so using anycast.censurfridns.dk or google's 8.8.8.8.
You can read more about it in my [next post](Using%20DHCP).

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---
title: Using DHCP for the unikernels
author: reynir
---
# Using DHCP for the unikernels
TBD...