PXE Boot Server for Ubuntu 22.04.5 Live Server¶

🎯 What You’ll Achieve¶

By following this guide, you will:

✅ Set up a PXE boot environment on a Linux machine using Docker
✅ Use pxelinux.0 as the bootloader to support BIOS PXE clients
✅ Serve the Ubuntu 22.04.5 Live Server ISO over HTTP using nginx
✅ Let PXE clients boot and start the manual Ubuntu installer entirely over the network
✅ Avoid the need for dnsmasq, iPXE, or autoinstall
✅ Use Fortigate as the DHCP provider to point PXE clients to the correct boot server

📁 Project Directory Structure¶

~/pxe-ipxe-server/
├── Dockerfile
├── nginx.conf
├── tftp/
│   ├── pxelinux.0
│   ├── ldlinux.c32
│   ├── vmlinuz
│   ├── initrd
│   └── pxelinux.cfg/
│       └── default
├── http/
│   └── ubuntu-22.04.5-live-server-amd64.iso

🪜 Step-by-Step Instructions¶

📥 Download Ubuntu Live Server ISO¶

cd ~/Downloads
wget https://releases.ubuntu.com/22.04/ubuntu-22.04.5-live-server-amd64.iso

🔧 Mount ISO and Extract Boot Files¶

sudo mkdir -p /mnt/ubuntu_iso
sudo mount -o loop ubuntu-22.04.5-live-server-amd64.iso /mnt/ubuntu_iso

mkdir -p ~/pxe-ipxe-server/tftp ~/pxe-ipxe-server/http
cp /mnt/ubuntu_iso/casper/vmlinuz ~/pxe-ipxe-server/tftp/
cp /mnt/ubuntu_iso/casper/initrd ~/pxe-ipxe-server/tftp/
cp ~/Downloads/ubuntu-22.04.5-live-server-amd64.iso ~/pxe-ipxe-server/http/

sudo umount /mnt/ubuntu_iso

📦 Download PXELINUX Bootloader Files¶

cd ~/pxe-ipxe-server/tftp

# Download pxelinux.0 from Ubuntu's archive
wget http://archive.ubuntu.com/ubuntu/dists/focal/main/installer-amd64/current/legacy-images/netboot/pxelinux.0

# Copy ldlinux.c32 from local syslinux install
cp /usr/lib/syslinux/modules/bios/ldlinux.c32 .

📝 Create PXELINUX Config¶

mkdir -p ~/pxe-ipxe-server/tftp/pxelinux.cfg
vi ~/pxe-ipxe-server/tftp/pxelinux.cfg/default

Paste:

pxelinux.cfg/default

DEFAULT install

LABEL install
  KERNEL vmlinuz
  INITRD initrd
  APPEND root=/dev/ram0 ramdisk_size=1500000 ip=dhcp boot=casper url=http://192.168.2.19/ubuntu-22.04.5-live-server-amd64.iso ---

⚙️ Create nginx.conf¶

nginx.conf

worker_processes  1;

events {
    worker_connections  1024;
}

http {
    include       mime.types;
    default_type  application/octet-stream;

    server {
        listen 80;
        location / {
            root /srv/http;
            autoindex on;
        }
    }
}

🐳 Create container image¶

Dockerfile

FROM alpine:latest

RUN apk add --no-cache nginx tftp-hpa

COPY tftp /srv/tftp
COPY http /srv/http
COPY nginx.conf /etc/nginx/nginx.conf
RUN mkdir -p /run/nginx

EXPOSE 69/udp 80

CMD sh -c "nginx && in.tftpd --foreground --address :69 --secure /srv/tftp"

🧱 Build and Run Your Docker PXE Server¶

cd ~/pxe-ipxe-server
docker build -t pxe-server .
docker run --rm -it --net=host pxe-server

📡 Fortigate DHCP Configuration¶

config system dhcp server
    edit <your_dhcp_pool_id>
        set next-server 192.168.2.19
        set filename "pxelinux.0"
    next
end

✅ PXE Boot Result¶

When you boot a PXE BIOS client:
It gets an IP via DHCP from Fortigate
Downloads pxelinux.0 and ldlinux.c32 via TFTP
Loads the kernel + initrd
Fetches the full ISO via HTTP
Starts the manual Ubuntu installer