When you first boot up your firewall, you may find that not all of your devices work. This is particularly likely in the case of network adapters. The reason for this is that the operating system only probes for a small subset of possible device configurations, and thus does not find the right results for many configurations.
This is not a serious problem, as the kernel can be patched with new values. You do need to be very careful about what kernel settings you change though. The firewall will allow you to change the setup not only of your network cards, but of your disk controller cards as well. Using the wrong information for the disk controller cards can result in your firewall no longer being able to boot.
To prevent this situation from arising, we recommend that you be absolutely certain of your hardware device configuration before using fwadmin to change it. Don't alter disk controller settings if your system is working unless the disk controller is a secondary controller that is not properly detected (for example if you have an IDE disk controller and later add a SCSI controller for a tape drive or CD-ROM, or vice versa). If you aren't sure of what your hardware settings are, perhaps due to missing documentation, there are a few guidelines that can help. You should examine the output of the dmesg command (also accessible from fwadmin's Main Screen by pressing `Boot Messages'). This will give a list of what devices were probed and which were found. If the list reports that a network card was found but you later get device timeouts for the device, this almost always means that the I/O port base address is correct for the device but the interrupt is wrong (an exception is Ethernet devices, which may report timeouts if they are not connected to any physical medium).
The fields in the Device Setup Screen are (see Figure 4.5):
You can specify up to three network cards, for the internal, external, and DMZ network interfaces. The external interface may be PPP or SLIP rather than Ethernet, and the DMZ network is optional.
PCI Plug and Play cards are automatically detected, and so do not need to be configured from this screen. ISA Plug and Play cards are not currently supported in Plug and Play mode, but must be manually configured.
The Hardware Setup Screen (Figure 4.6) lets you modify the interrupt levels, I/O port base addresses, memory base addresses, and DMA channels used by the various hardware devices in your system. You should only make changes here if you are sure that the values you enter are correct.
For each device that can be configured there are four fields:
Although each device has all four fields, not all devices use all fields (in fact most devices use only two, the interrupt and I/O port base address). A value entered in fields which is not applicable to a particular device will simply be ignored.
If you save the changes, the kernel itself will not be modified until you save the changes in the Device Setup Screen.
![\includegraphics[width=14cm,height=10cm]{kernsetup.ps}](img24.png)
![\includegraphics[width=14cm,height=10cm]{hwaresetup.ps}](img25.png)