dhcpd não permite opção de nome de arquivo com dois pontos

Question

Por algum motivo, tftpboot não funciona com dois pontos no parâmetro filename :

group {
  filename "node7:linux/pxelinux.0";

  host machine_7a  {
    hardware ethernet 02:01:02:02:01:11;
    fixed-address 192.168.10.8;
  }

  host machine_7b {
    hardware ethernet 02:01:02:02:01:12;
    fixed-address 192.168.10.9;
  }
}

Se eu alterar os dois pontos para um traço - , as máquinas remotas poderão fazer o tftpboot bem. Você sabe por que dois pontos no parâmetro filename não funcionam?

UPDATE :

Saída de /var/log/message quando defino o filename para "node7-linux/pxelinux.0"

Jan 22 22:52:48 linux-yp1y dhcpd: DHCPDISCOVER from 02:01:02:02:01:11 via br0
Jan 22 22:52:48 linux-yp1y dhcpd: DHCPOFFER on 192.168.10.7 to 02:01:02:02:01:11 via br0
Jan 22 22:52:49 linux-yp1y dhcpd: DHCPDISCOVER from 02:01:02:02:01:11 via br0
Jan 22 22:52:49 linux-yp1y dhcpd: DHCPOFFER on 192.168.10.7 to 02:01:02:02:01:11 via br0
Jan 22 22:52:51 linux-yp1y dhcpd: DHCPREQUEST for 192.168.10.7 (192.168.10.1) from 02:01:02:02:01:11 via br0
Jan 22 22:52:51 linux-yp1y dhcpd: DHCPACK on 192.168.10.7 to 02:01:02:02:01:11 via br0
Jan 22 22:52:51 linux-yp1y atftpd[12967]: Serving node7-linux/pxelinux.0 to 192.168.10.7:1024
Jan 22 22:52:51 linux-yp1y dhcpd: DHCPDISCOVER from 02:01:02:02:01:11 via br0
Jan 22 22:52:51 linux-yp1y dhcpd: DHCPOFFER on 192.168.10.7 to 02:01:02:02:01:11 via br0
Jan 22 22:52:52 linux-yp1y dhcpd: DHCPDISCOVER from 02:01:02:02:01:11 via br0
Jan 22 22:52:52 linux-yp1y dhcpd: DHCPOFFER on 192.168.10.7 to 02:01:02:02:01:11 via br0
Jan 22 22:52:54 linux-yp1y dhcpd: DHCPREQUEST for 192.168.10.7 (192.168.10.1) from 02:01:02:02:01:11 via br0
Jan 22 22:52:54 linux-yp1y dhcpd: DHCPACK on 192.168.10.7 to 02:01:02:02:01:11 via br0
Jan 22 22:52:54 linux-yp1y atftpd[12967]: Serving node7-linux/pxelinux.cfg/default to 192.168.10.7:1024
Jan 22 22:52:54 linux-yp1y atftpd[12967]: Serving node7-linux/vmlinuz to 192.168.10.7:1025
Jan 22 22:52:55 linux-yp1y atftpd[12967]: Serving node7-linux/initrd to 192.168.10.7:1026
Jan 22 22:53:14 linux-yp1y dhcpd: DHCPDISCOVER from 02:01:02:02:01:11 via br0
Jan 22 22:53:14 linux-yp1y dhcpd: DHCPOFFER on 192.168.10.7 to 02:01:02:02:01:11 via br0
Jan 22 22:53:14 linux-yp1y dhcpd: DHCPREQUEST for 192.168.10.7 (192.168.10.1) from 02:01:02:02:01:11 via br0
Jan 22 22:53:14 linux-yp1y dhcpd: DHCPACK on 192.168.10.7 to 02:01:02:02:01:11 via br0
Jan 22 22:53:15 linux-yp1y dhcpd: DHCPDISCOVER from 02:01:02:02:01:12 via br0
Jan 22 22:53:15 linux-yp1y dhcpd: DHCPOFFER on 192.168.10.8 to 02:01:02:02:01:12 via br0
Jan 22 22:53:15 linux-yp1y dhcpd: DHCPREQUEST for 192.168.10.8 (192.168.10.1) from 02:01:02:02:01:12 via br0
Jan 22 22:53:15 linux-yp1y dhcpd: DHCPACK on 192.168.10.8 to 02:01:02:02:01:12 via br0

Saída de /var/log/message quando defino o filename para "node7:linux/pxelinux.0" :

Jan 22 23:16:57 linux-yp1y kernel: [343021.700191] br0: port 6(vnet6) entering forwarding state
Jan 22 23:16:57 linux-yp1y kernel: [343021.700296] device vnet6 left promiscuous mode
Jan 22 23:16:57 linux-yp1y kernel: [343021.700302] br0: port 6(vnet6) entering disabled state
Jan 22 23:16:57 linux-yp1y kernel: [343021.721423] br0: port 7(vnet7) entering forwarding state
Jan 22 23:16:57 linux-yp1y kernel: [343021.721467] device vnet7 left promiscuous mode
Jan 22 23:16:57 linux-yp1y kernel: [343021.721470] br0: port 7(vnet7) entering disabled state
Jan 22 23:16:58 linux-yp1y kernel: [343021.742969] br2: port 4(vnet8) entering forwarding state
Jan 22 23:16:58 linux-yp1y kernel: [343021.743040] device vnet8 left promiscuous mode
Jan 22 23:16:58 linux-yp1y kernel: [343021.743042] br2: port 4(vnet8) entering disabled state
Jan 22 23:16:58 linux-yp1y ifdown:     vnet6     
Jan 22 23:16:58 linux-yp1y ifdown: Interface not available and no configuration found.
Jan 22 23:16:58 linux-yp1y ifdown:     vnet7     
Jan 22 23:16:58 linux-yp1y ifdown: Interface not available and no configuration found.
Jan 22 23:16:58 linux-yp1y ifdown:     vnet8     
Jan 22 23:16:58 linux-yp1y ifdown: Interface not available and no configuration found.
Jan 22 23:17:01 linux-yp1y kernel: [343025.377050] device vnet6 entered promiscuous mode
Jan 22 23:17:01 linux-yp1y kernel: [343025.393810] br0: port 6(vnet6) entering forwarding state
Jan 22 23:17:01 linux-yp1y kernel: [343025.393814] br0: port 6(vnet6) entering forwarding state
Jan 22 23:17:01 linux-yp1y kernel: [343025.449562] device vnet7 entered promiscuous mode
Jan 22 23:17:01 linux-yp1y kernel: [343025.466276] br0: port 7(vnet7) entering forwarding state
Jan 22 23:17:01 linux-yp1y kernel: [343025.466280] br0: port 7(vnet7) entering forwarding state
Jan 22 23:17:01 linux-yp1y kernel: [343025.557549] device vnet8 entered promiscuous mode
Jan 22 23:17:01 linux-yp1y kernel: [343025.574265] br2: port 4(vnet8) entering forwarding state
Jan 22 23:17:01 linux-yp1y kernel: [343025.574270] br2: port 4(vnet8) entering forwarding state
Jan 22 23:17:03 linux-yp1y dhcpd: DHCPDISCOVER from 02:01:02:02:01:11 via br0
Jan 22 23:17:03 linux-yp1y dhcpd: DHCPOFFER on 192.168.10.7 to 02:01:02:02:01:11 via br0
Jan 22 23:17:04 linux-yp1y dhcpd: DHCPDISCOVER from 02:01:02:02:01:11 via br0
Jan 22 23:17:04 linux-yp1y dhcpd: DHCPOFFER on 192.168.10.7 to 02:01:02:02:01:11 via br0
Jan 22 23:17:05 linux-yp1y kernel: [343029.580829] br2: port 4(vnet8) entering forwarding state
Jan 22 23:17:06 linux-yp1y dhcpd: DHCPREQUEST for 192.168.10.7 (192.168.10.1) from 02:01:02:02:01:11 via br0
Jan 22 23:17:06 linux-yp1y dhcpd: DHCPACK on 192.168.10.7 to 02:01:02:02:01:11 via br0
Jan 22 23:17:06 linux-yp1y dhcpd: DHCPDISCOVER from 02:01:02:02:01:12 via br0
Jan 22 23:17:06 linux-yp1y dhcpd: DHCPOFFER on 192.168.10.8 to 02:01:02:02:01:12 via br0
Jan 22 23:17:07 linux-yp1y dhcpd: DHCPDISCOVER from 02:01:02:02:01:12 via br0
Jan 22 23:17:07 linux-yp1y dhcpd: DHCPOFFER on 192.168.10.8 to 02:01:02:02:01:12 via br0
Jan 22 23:17:09 linux-yp1y dhcpd: DHCPREQUEST for 192.168.10.8 (192.168.10.1) from 02:01:02:02:01:12 via br0
Jan 22 23:17:09 linux-yp1y dhcpd: DHCPACK on 192.168.10.8 to 02:01:02:02:01:12 via br0
Jan 22 23:17:12 linux-yp1y kernel: [343035.804008] vnet8: no IPv6 routers present
Jan 22 23:17:12 linux-yp1y kernel: [343036.148005] vnet7: no IPv6 routers present
Jan 22 23:17:12 linux-yp1y kernel: [343036.397004] vnet6: no IPv6 routers present
Jan 22 23:17:24 linux-yp1y dhcpd: DHCPDISCOVER from 02:01:02:02:01:11 via br0
Jan 22 23:17:24 linux-yp1y dhcpd: DHCPOFFER on 192.168.10.7 to 02:01:02:02:01:11 via br0
Jan 22 23:17:25 linux-yp1y dhcpd: DHCPDISCOVER from 02:01:02:02:01:11 via br0
Jan 22 23:17:25 linux-yp1y dhcpd: DHCPOFFER on 192.168.10.7 to 02:01:02:02:01:11 via br0
Jan 22 23:17:27 linux-yp1y dhcpd: DHCPREQUEST for 192.168.10.7 (192.168.10.1) from 02:01:02:02:01:11 via br0
Jan 22 23:17:27 linux-yp1y dhcpd: DHCPACK on 192.168.10.7 to 02:01:02:02:01:11 via br0
Jan 22 23:17:27 linux-yp1y dhcpd: DHCPDISCOVER from 02:01:02:02:01:12 via br0
Jan 22 23:17:27 linux-yp1y dhcpd: DHCPOFFER on 192.168.10.8 to 02:01:02:02:01:12 via br0
Jan 22 23:17:28 linux-yp1y dhcpd: DHCPDISCOVER from 02:01:02:02:01:12 via br0
Jan 22 23:17:28 linux-yp1y dhcpd: DHCPOFFER on 192.168.10.8 to 02:01:02:02:01:12 via br0
Jan 22 23:17:30 linux-yp1y dhcpd: DHCPREQUEST for 192.168.10.8 (192.168.10.1) from 02:01:02:02:01:12 via br0
Jan 22 23:17:30 linux-yp1y dhcpd: DHCPACK on 192.168.10.8 to 02:01:02:02:01:12 via br0

    

Answer 1

O PXELINUX suporta as seguintes convenções especiais de nome de caminho:

:: nome do arquivo     Suprime o prefixo de nome de arquivo comum, ou seja, passa a string "filename" sem modificação para o servidor.

endereço IP :: nome do arquivo      (e.g. node7::filename)     Suprima o prefixo de nome de arquivo comum e envie uma solicitação para um servidor TFTP alternativo.     Em vez de um endereço IP, um nome DNS pode ser usado.     Será considerado totalmente qualificado se contiver pontos; caso contrário, o domínio local, conforme relatado pelo servidor DHCP (opção 15), será adicionado.

O símbolo de dois pontos ("::") foi escolhido porque é improvável que entre em conflito com o uso do sistema operacional.

Atribuição: aqui