Best of Technical Support

Our experts answer your technical questions.
Netscape On MkLinux

I have installed MkLinux on my Mac 6100. I log in and ftp Netscape. When I try to run the executable I get an error message saying I can't run the binary. —Manny Duarte

No MkLinux Binary

As far as I know, Netscape does not support MKLinux. The binary they supply for Linux is compiled for Intel CPUs. It will not work on a Mac. —Bob Hauck, Wasatch Communications Group bobh@wasatch.com

Terminating pppd

I am running kernel 1.2.13 and pppd 2.1.2 on a remote machine and kernel 2.0.18 and pppd 2.2.0 on a local machine to connect to the remote machine by modem. When the modem drops carrier (due to line noise, etc.) the remote pppd process remains active, preventing getty accepting any more connections until pppd is killed.

Is it possible to have the remote pppd terminate automatically when the modem drops the carrier? —Eskinder Mesfin

Running pppd Manually

The modem option does exactly that, assuming that your modem is set up to have the DCD signal follow the carrier state and that your cables pass all of the relevant signals through to the serial port. Most modems will operate DCD in the desired mode if you include AT&C1 in the init string.

However, if you are manually running pppd on the remote machine after logging in to a shell, there is a caveat. In that case you need to exec pppd rather than simply running it.

If you just run pppd from the command line, the shell, rather than the pppd process, will get the SIGHUP signal when you hang up. The shell will terminate but leave the pppd daemon running. Instead, do exec pppd. This will replace the running shell with pppd so that the hang-up signal will work correctly. —Bob Hauck, Wasatch Communications Group bobh@wasatch.com

Generating RARP Requests

I need to set up a large number of Linux boxes as X-terminals. I would like to automate the addressing of these boxes through RARP, preferably. I have had little trouble learning how to make a Linux box answer RARP queries, but I can't seem to make it generate one. Any help you could offer would be appreciated. —George

Enabling RARP

The kernel can do it. You can boot a kernel, have it generate a RARP request, and then use the machine that answers as an NFS server. It can do the same using the BOOTP protocol as well. These options must be enabled during the make config of the kernel.

I suspect what you want is something like what a Sun workstation does, which is to get a kernel from the network starting with a RARP request. That kind of thing can be done only with special ROMs available only for certain Ethernet cards. You can likely find information at http://sunsite.unc.edu/linux. I recommend using small hard disks or booting a kernel from floppy to an NFS server. It is much easier to work with. —Donnie Barnes, Red Hat Software redhat@redhat.com

Plug and Play Modems

I used Windows 95 before Linux; that's why I got a plug and play modem. It works with Windows 95 but it does not work in Linux. Why? —Stou Sandalski

Two Types of Plug and Play

There are two different types of internal modems that fall into the plug and play category. The first is a standard modem that is simply configured at boot time to determine what COM port it will provide. The second is called a WinModem.

A WinModem does not have a UART, which is what makes a normal serial port tick. Instead, they knock down the price of the modem by $10-$20 and eliminate this normally necessary component of any serial port or modem. It is replaced with a software driver that emulates the UART's functionality.

If you have, or think you have, such a modem, your only hope would be to ask the manufacturer whether they support Linux for that modem. If not, the modem cannot be used under Linux. If you do not have a WinModem, you should be fine, provided you set the modem up correctly.

No two modems are identical. Your best bet is to consult the manufacturer. In most cases, if you do not have a product that will work under Linux, they will provide an upgrade at a very low cost. —Chad Robinson, BRT Technical Services Corporationredhat@redhat.com

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