Explaining the CapaInstaller PXE Bootloader
Introduction
Section titled “Introduction”The following information is the description of the CapaInstaller PXE Bootloader.
CapaInstaller PXE Bootloader is a bootstrap program to be used for PXE booting client computers. PXE in general integrates with the DHCP technology to provide information for clients on how to execute the PXE boot.
The main feature of CapaInstaller PXE Bootloader is the ability to load boot images from a boot server and allow client machines to boot using these images.
Some of the unique features of CapaInstaller PXE Bootloader are
- Subnet awareness
- Password protection
- Advanced menu options
- Failover
- MAC and model differentiation
- Boot several different WinPE images from one TFTP server
| The boot process is controlled by two items, the configuration file and the settings for the base boot image. The application “pxconfig.exe” is used to configure the base boot image, the following table describes the options available: |
| Element | Description |
| Configuration file | Name of the configuration file on the TFTP server. Can include path. If the file or pathname does not begin with "", the path will be relative to the bootstrap file directory for that client. |
| IP configuration directory MAC configuration directory | PXE Boot can initially look for a configuration file of the type 1.2.3.4.cfg or 010203040506.cfg, where the numbers are the IP number or the MAC address of the booting client. These options specify the directories on the TFTP server to use for these files. If the pathname does not begin with "", the path will be relative to the bootstrap file directory for that client. |
| Menu text | String to show as a header for a boot menu. Can be changed in the configuration file. The maximum length of 64 characters. |
| Admin Menu text | String to show as a header for an administrative boot menu. Can be changed in the configuration file. The maximum length of 64 characters. |
| Admin section name | Section to enter when “Administrative Menu” is selected by the keypress. |
| Prompt text | Text to show as PXE Boot prompt. Not showing “Ctrl-X” (key configurable) would give a, very simple protection against unintended PXE boot. |
| Menu prompt text | Text to show as prompt for the PXE boot menu. |
| Password prompt | The default is “Enter the password for”. The section name will be added by PXE Boot. |
| Option 54 IP priority Siaddr IP priority Option 66 IP string priority | The “Boot Server ACK Packet” can contain the IP number of the TFTP server in different ways, depending on how the DHCP server is set up. PXE Boot will look for a TFTP server IP address in the selected priority, where 1 is the highest priority and 0 is for do not use. The most common settings are 2-1-0 and 1-0-0, depending on the network. |
| Enable IP configuration files Enable MAC configuration files | Enables the use of IP and MAC configuration files. These must be activated for options “IP configuration directory” and “MAC configuration directory” respectively to work. |
| Show A: as B: | If yes, an existing A: floppy drive will be accessible as B: when the PXE Boot floppy is running. |
| WINS support | If yes, the image file name in the configuration file can include the server name, and the image can be downloaded from that server. PXE Boot will look for an option 44 WINS/NBNS Server IP address. If not available, a name request will be broadcast. |
| Handle interrupt 19h reboot | If yes, PXE boot will intercept interrupt 19h, and reboot the floppy image locally if interrupt 19h is called. |
| Display PXE Boot prompt | If yes, PXE Boot will display a prompt, and initiate local boot if Ctrl-X (configurable) is not pressed at the client keyboard within a user-defined number of seconds. If Ctrl-A (configurable) is pressed instead, an administrative menu of boot images (if any) will be displayed. |
| Alt-key admin menu | If yes, pressing the Alt key during the PXE Boot load will invoke the administrative menu or administrative section. Can be used if the boot prompt is not set. |
| Intercept interrupt 10h | Avoid blank screen when booting Windows Vista PE. If there is a Vista PE boot problem, try disabling this feature, or see the next option. |
| Interrupt 10h method 2 | Selecting “no” will use the version 2.01 intercept method, if “Intercept interrupt 10h” is enabled. |
| Intercept TFTP | Makes it possible to boot Windows Vista PE from another 5 letter directory than \Boot. This is required for WinPE 2.0 build with WAIK 1.0. |
| Prompt sound | If set, a sound will be sent to the internal speaker when the boot prompt is displayed. |
| Deskpro EN fix | Fix a screen compatibility problem, seen in a Deskpro EN PC. Disabling the fix can enhance PXE Boot display. |
| Prompt key Prompt admin key | Keyboard keys to accept a prompt. Default is Ctrl-X, and Ctrl-A for the administrative menu. Available are F1 to F12, Alt-F1 to Alt-F12, Ctrl-F1 to Ctrl-F12, Alt-A to Alt-Z and Ctrl-A to Ctrl-Z. The prompt texts have to be edited too. |
| Seconds before error reboot | Seconds to wait before the reboot if PXE Boot is set to reboot for an error condition. |
| Extended BIOS data area KB | If this value is set to 0, PXE Boot will automatically determine the amount of memory to reserve for the Extended BIOS data area. If the automatic method does not work, a value can be set. |
| Prompt seconds | Seconds to show the prompt and menu prompt. |
| Menu timeout seconds | Seconds for menu timeout, if timeout selected in the configuration file. Maximum 99 seconds. |
Commandline arguments for “pxconfig.exe”
pxconfig [<filename> <priority> <priority>
<priority> update nomessagebox ]
| Element | Description |
| filename | The base boot to focus on. |
| IP54 | Priority value to set. |
| IPSI | Priority value to set. |
| IP66 | Priority value to set. |
| Update | Update the focused base boot image to the latest version, all settings will be preserved. |
| Nomessagebox | Do not display a message box after performing a command-line task. |
Configuration file
| The configuration files can be written in one of two formats The old format supports a standard menu and an administrative, Automatic IP range based image selection and model-based selection. The new format supports advanced menu structures, password protects, failover and it allows the user to combine the different options in many ways, enabling a lot of setup options. |
The old format
| The section describes the old format or simple format. This format is similar to an .ini but has some differences, so it is not to be treated as such. An example of a configuration file:\ |
=
menu
Menu
“CapaInstaller OSD - SRV01” = ”\boot\pxeboot.n12”
“CapaInstaller OSD - SRV02” = ”\192.168.1.201\boot\pxeboot.n12”
Administrative Menu
“CapaInstaller OSD Test setup” =
”\TEST1\pxeboot.n12”
The file is built using sections, of which there are four different
flavours:
| Element | Description |
| (default) | This section is not really a section, but when the boot loader reads a = with no information to the left, this considered the default option, the righthand side of the line, can refer to a bracket section, menu. |
| IP Ranges | The boot loader will scan any IP Ranges section for a subnet or ip address matching that of the client and if one is found, the referred image will be loaded. |
| Prestage | The bootloader can look for MAC address or SMBIOS Model ID matches in the Prestage section, and if a match is found the image is loaded. Consider this option if the need for booting a specific image for a certain type of hardware is required. |
| Menu | The menu is the list of images to display if no match was found in either an IP Range or a Prestage value. |
| Administrative menu | Instead of activating the default menu, any matching IP Range or Prestage section, the Bootloader will load the Administrative Menu. Consider using the “Alt-key admin menu” to “hide” the administrative menu from normal users. |
Image references
| CapaInstaller PXE BootLoader supports 3 different types of boot images - Microsoft pxeboot format, ie WinPE 2.0 wim images - Native PXE image simulating a floppy disk boot - Chained bootloader images The reference to the specific image may contain a reference to a remote TFTPD server. All reference are in the format \<server><path><imagename> |
Some examples:
| Element | Description |
| Native image | “Windows 98”=win98.img |
| WinPE 2.0 | “WinPE”=”\boot\pxeboot.n12” |
| Remote WinPE 2.0 image | “WinPE remote”=”\192.168.1.200\boot\pxeboot.n12” |
| Remote chained bootloader image | \192.168.1.200\cipcc.0 |
The new format
| The section describes the new format or the advanced format. This format is an .ini. An example of a configuration file using the advanced format: |
IP Ranges
192.168.1 = “Administrative Menu”
Menu
“CapaInstaller OSD - SRV01” = ”\boot\pxeboot.n12”
“CapaInstaller OSD - SRV02” = ”\192.168.1.201\boot\pxeboot.n12”
“Adminstrative Menu (protected)”=
“Administrative Menu”
Administrative Menu
Password=23234151342342
“CapaInstaller OSD Test setup” =
TestImage
TestImage
image = WinXP.img
backup = \192.168.1.210\WinXP.img
backup = \192.168.1.211\WinXP.img
| The major difference between the new format and the old is that all references in the new format can be either an image reference or a section describing a menu or an image. |
| Element | Description |
| IP Ranges | The boot loader will scan any IP Ranges section for a subnet or IP address matching that of the client and if one is found, the reference will be followed. |
| Prestage | The bootloader can look for MAC address or SMBIOS Model ID matches in the Prestage section, and if a match is found the reference will be followed. Consider this option if the need for booting a specific image for a certain type of hardware is required. |
| Administrative menu | Instead of activating the default menu, any matching IP Range or Prestage section, the Bootloader will load the Administrative Menu. Consider using the “Alt-key admin menu” to “hide” the administrative menu from normal users. |
| Bracket sections | A bracket section is named by the reference key (the text between the brackets) Such a section can refer to either a menu or an image. |
Image references new format
| CapaInstaller PXE BootLoader supports 3 different types of boot images - Microsoft pxeboot format, ie WinPE 2.0 wim images - Native PXE image simulating a floppy disk boot - Chained bootloader images The reference to the specific image may contain a reference to a remote TFTPD server. |
Some examples:
| Element | Description |
| Native image | “Windows 98”=win98.img |
| WinPE 2.0 | “WinPE”=”\boot\pxeboot.n12” |
| Remote WinPE 2.0 image | “WinPE remote”=”\192.168.1.200\boot\pxeboot.n12” |
| Remote chained bootloader image | \192.168.1.200\cipcc.0 |
| Advanced image reference | By using a bracket section, it is possible to define advanced image references, containing failover locations and image specific passwords. “CapaInstaller OSD Test setup” = TestImage TestImage password=23234151342342 image = WinXP.img backup = \192.168.1.210\WinXP.img backup = \192.168.1.211\WinXP.img In the above sample, TestImage refers to the bracket section describing the image. |
Usage tips
-
Pressing Esc at a boot prompt will escape the prompt.
-
Pressing Esc in a menu will escape the menu and boot locally.
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A menu choice can be entered by pressing Enter or right.
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When in a menu, the administrative menu (or alternative section) can be entered by pressing Ctrl-A (prompt admin key, configurable).
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When in a menu, PXE Boot can be re-initiated by pressing Ctrl-X (prompt key, configurable), backspace or left.
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When in a password prompt, PXE Boot can be re-initiated by pressing Esc.
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The administrative menu (if any) is invoked by pressing Ctrl-A (configurable) at the prompt instead of Ctrl-X (configurable).
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If the prompt is not defined, PXE Boot can be configured to invoke the administrative menu if Alt is pressed during PXE Boot load.
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Unused sectors can be cut from the end of image files, as long as the size is divisible with 512, and as long as 1.44 MB floppy images are larger than 65,536 bytes, and 2.44 MB floppy images are larger than 1,474,560 bytes.
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Note that the bootstrap program can chain to another copy in another directory. In this case, the initial backslash should be removed from the option “Configuration file”.
Client requirements
Clients must implement PXE (Preboot Execution Environment) specification
2.1.