netboot

netboot

configuration > server > netboot

Setting up a netboot server is surprisingly easy, but I could not find comprehensive guides. What you really need:

  • DHCP Server, from which your client receives an IP-Address and the Address to a tftp server
  • TFTP Server, where a bootloader and one or more images are located

TFTP Server

First install a tftp server package with support for xinet (usually included in plain xinet)

xinetd is a daemon, which listens on specified ports and pipes the traffic to a program one can specify in config. In this case we want a tftp config file, where you can also specify a root path for your tftp server:

# /etc/xinetd.d/tftp`
service tftp
{
        socket_type             = dgram
        protocol                = udp
        wait                    = yes
        user                    = root
        server                  = /usr/sbin/in.tftpd
        server_args             = -s /home/max/kolibrios/netboot/
        disable                 = no
        per_source              = 11
        cps                     = 100 2
        flags                   = IPv4
}

Note: If you are using SELinux and want to use a directory in a users home directory (as in the example above), you will have to tell SELinux about it:

setsebool -P tftp_home_dir 1

DHCP Server

The installation package is most likely called dhcp or dhcp-server or dhcpd. It will not be preinstalled in most cases.

The most important part in our dhcpd.conf-file is the subnet part. It acts like a filter and will only become active for interfaces, which are in its IP range, starting with 192.168.178.0 in the following example:

# /etc/dhcp/dhcpd.conf

allow booting;
allow bootp;

option space PXE;
option PXE.mtftp-ip    code 1 = ip-address;
option PXE.mtftp-cport code 2 = unsigned integer 16;
option PXE.mtftp-sport code 3 = unsigned integer 16;
option PXE.mtftp-tmout code 4 = unsigned integer 8;
option PXE.mtftp-delay code 5 = unsigned integer 8;
option arch code 93 = unsigned integer 16; # RFC4578

subnet 192.168.178.0 netmask 255.255.255.0
{
        option routers 192.168.178.1;
        range 192.168.178.60 192.168.178.100;
        next-server 192.168.178.26;
        filename "pxelinux.0";
}

Open your firewall

Do not forget to open the firewall ports for DHCP Server!

We need:

  • 67/udp, 68/udp for dhcpd
  • 69/udp for the TFTP server

Now get something running…

Put files from the syslinux project in your tftp-root-directy, namely:

  • /usr/share/syslinux/vesamenu.c32

  • /usr/share/syslinux/memdisk

  • KolibriOS can good be used for testing because it is so tiny.

  • a file called pxelinux.cfg is required for configuration, like so:

    # FTP-ROOT-PATH/pxelinux.cfg/default`
    UI vesamenu.c32
    
    LABEL kolibri.iso
      LINUX memdisk
      INITRD kolibri.iso
      APPEND iso
    
    LABEL kolibri.img
      LINUX memdisk
      INITRD kolibri.img
      APPEND raw
    
  • Your network computer should now be able to start

Troubleshooting

You can run qemu in order to test whether or not your tftp folder is correctly set up:

qemu-kvm -boot n -net user,tftp=/path/to/tftp,bootfile=/pxelinux.0
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