DHCP Server config:


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 PXE.discovery-control      code 6 = unsigned integer 8;
option PXE.discovery-mcast-addr   code 7 = ip-address;
option routers;
ddns-update-style none;
use-host-decl-names on;
option domain-name-servers,;
subnet netmask {
  option routers;
  option subnet-mask;
  option domain-name-servers,;
  #Range of IPs to dynamically assign.  Optional.
  range ;
  default-lease-time 120;
  max-lease-time 120;
  #Next line should be whatever server hosts PXE files.
  #Uncomment next line for TFTP running in chrooted environment.
  filename "pxelinux.0";

  #Uncomment next line for TFTP running not in chroot environment.
  #filename "/var/lib/tftpboot/pxelinux.0";

  group {
    host new_host {
      hardware ethernet 08:00:27:07:80:FE;
      option routers;
#end optional part


Set the interfaces that you want to use in /etc/default/isc-dhcp-server:


TFTP Server config:

apt-get install tftpd-hpa



Here is a tree of tftp folder:

├── initrd.img-3.13-0.bpo.1-amd64
├── initrd.img-3.2.0-4-amd64
├── install.img
├── mboot.c32
├── menu.c32
├── pxelinux.0
├── pxelinux.cfg
│   ├── 01-08-00-27-07-80-fe
│   └── default
├── vmlinuz   
├── vmlinuz-3.13-0.bpo.1-amd64
├── vmlinuz-3.2.0-4-amd64
└── xen.gz

Example config /srv/tftp/pxelinux.cfg/default:

#default Debian
default menu.c32
menu title Boot Menu
prompt 10
timeout 10
label Debian
        kernel vmlinuz-3.13-0.bpo.1-amd64
        append rw initrd=initrd.img-3.13-0.bpo.1-amd64 root=/dev/nfs ip=dhcp nfsroot=
label XenServer
        menu label XenServer
        kernel mboot.c32
        #append xen.gz --  vmlinuz ip=dhcp root=/dev/nfs nfsmount= iso_filename=XenServer-6.2.0-install-cd.iso
        append xen.gz dom0_max_vcpus=4 dom0_mem=1024M console=vga --- vmlinuz xencons=hvc console=hvc0 console=tty0 answerfile= install --- install.img