This was tested on NetBSD 3.99.16, however the instructions should apply to other versions as well. I have attempted to flag steps where you may run into version incompatabilities with “Version Note”.

To PXEboot install NetBSD we will first need to configure a tftp server. You will need to insure that tftp is uncommented from inetd.conf and that inetd is enabled to run.

/etc/inetd.conf

  tftp dgram udp wait root /usr/libexec/tftpd tftpd -l  -s /tftpboot

 
/etc/rc.conf

  inetd=YES

 
Then we will need to create the /tftpboot directory and populate it. You will need the pxeboot_ia32.bin file (included in base.tgz) and the netbsd-INSTALL kernel.

Note: The installboot command is only necessary if you’re booting via a serial console (i.e. a Soekris box) as is the case in this paper.
Version Note: In the event you will need serial console support older versions of installboot may not support writing to pxeboot_ia32.bin, you will need to extract or build pxeboot_ia32_com0.bin.

  # cd /root
  # mkdir -p /tftpboot
  # gunzip netbsd-INSTALL.gz
  # cp netbsd-INSTALL /tftpboot
  # tar -zf base.tgz -x ./usr/mdec/pxeboot_ia32.bin
  # cd usr/mdec
  # installboot -e -o console=com0,speed=19200 pxeboot_ia32.bin
  # cp pxeboot_ia32.bin /tftpboot

 
Next you will need to configure dhcpd, and ensure it is enabled to run. You must configure dhcpd to serve pxeboot_ia32.bin.
Note: The next-server option is critical, it should refer to the tftp server IP address.
Note 2: The filename is given relative to the root-path.

/etc/dhcpd.conf

  default-lease-time 3600;
  max-lease-time 7200;
  option subnet-mask 255.255.255.0;
  option domain-name "domain.local";
  ddns-update-style ad-hoc;
  option domain-name-servers 10.0.10.100;
  subnet 10.0.10.0 netmask 255.255.255.0 {
                  option routers 10.0.10.1;
                  range 10.0.10.150 10.0.10.200;
                  next-server 10.0.10.5;
                  option root-path "/tftpboot";
                  filename "/pxeboot_ia32.bin";
  }

 
/etc/rc.conf

  dhcpd=YES

 
Make sure dhcpd and inetd are running, and then boot the host you wish to install.

  # /etc/rc.d/inetd restart
  # /etc/rc.d/dhcpd restart

 
If you are attempting to install onto a Soekris box, you must tell it to PXEboot

  > boot F0

 
You will see the PXEboot sequence, which will launch the NetBSD bootloader, you need to interrupt the NetBSD bootloader (hit spacebar several times). Once you are at the NetBSD bootloader prompt, enter the following:

  > boot tftp:netbsd-INSTALL

 
After this point, you will be booted into the NetBSD installation process you are used to.