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Our experts answer your technical questions.
Failure to Connect

My PPP connection is failing while using a modem to dial up to my ISP. My log indicates (after chat):

pppd:Serial Connection established
pppd:Using interface ppp0
pppd: Connect: ppp0 /dev/ttyS2
pppd: LCP: timeout sending Config-Requests
pppd: Modem Hangup pppd: Connection terminated
pppd: Exit

My options file with and without these lines given separately had the same effect:

lock passive lcp-echo-failure 10
lcp-echo-interval 400
Chat (tried different values):
 '' 'AT&F' (also used ATZ) 'OK' 'ATDTxxxxxx' 'CONNECT'
 '' 'login:' 'xxxxxx' 'password:' 'xxxxxx' 'TIMEOUT' '60'
pppd options (also tried 1500 for MTU and MRU:
hardflowcontrol=yes defroute=yes MRU=556
Do I need to include something more in my chat to make the modem wait longer ? Also, according to my ISP administrator, my machine is “not replying to LCP request”. My modem is a BestData 56K internal modem (#56SF), controller-based. I am using Red Hat 6.0 Intel. —Vijay Nunna,

There isn't anything else you should include in your chat script; however, some servers may be slow to start up the LCP communication, and thus your pppd daemon will timeout before then. To raise the number of LCP configure-request packets before pppd determines it is not responding, you can add the lcp-max-configure option to your /etc/ppp/options file, followed by the number of LCPs to send. For example, lcp-max-configure 30 would raise the number from the default of 10 to 30. You might also want to remove the—Andy Bradford,

You need to add debug on your pppd command line and look at the /var/log/messages file. You also want to replace chat with chat -v. Those two combined will give you lots of debug output and hopefully a better idea of what is failing and where. —Marc Merlin,

Dependency Question

I am trying to install a package that includes a Ghostscript driver for my printer. I'm getting dependency issues. The files required (as printed by rpm) are:

I've upgraded the libc libraries to glibc 2.1, but this seemed to have no effect. Looking at the dependency list, it also seems to need and without the GLIBC attached, and it has no problem finding these. I've looked at FTP sites for files with these names and cannot find them. Can anyone tell me what these are and if I need to find them, or whether I can tell rpm to ignore them? —Doug Morgan,

Often, a dependency on libc6 or libm6 means only that the binaries were compiled to use these versions of the libraries—they can often be recompiled against an older libc/libm without any problems. To do this, grab the SRPM (it should have the extension .src.rpm), do

rpm --rebuild

and install the resulting binary .rpm. Use this approach with caution, as there are applications that exhibit bugs under the older libc/libm (or won't compile). Still, in my experience, it generally works just fine. —Scott Maxwell,

Although you can install glibc 2.1 on a glibc 2.0 system, it may be better for you to upgrade your system to SuSE 6.3 instead. However, if you do have all the libraries installed, but for some reason the RPM database doesn't agree, you can force the package to install with rpm --nodeps package.i386.rpm.

Another option is to get the .src.rpm version of your package and rebuild it for your system: rpm --rebuild package.src.rpm. The resulting package should be in /usr/src/redhat/RPMS/i386/. —Marc Merlin,

Dueling Processors

I am thinking of building a dual-processor computer and wondering if Linux supports this. I have heard Linux is the best OS, and I have heard Windows NT is the only OS that supports multi-processing. —William Cason,

Linux does indeed support SMP. In fact, I use a fast dual-CPU Linux box at work. —Scott Maxwell,

Linux may or may not be “the best”, depending on what you're trying to do and what you're looking for. It does support multi-CPUs on recent kernels (2.2.x), and some distributions like Red Hat support SMP at install time. Some require you to compile your own kernel. —Marc Merlin,