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Mounting NFS

Best of Technical Support


Issue #65, September 1999

Our experts answer your technical questions.

Adding New Users

I am having extreme difficulty adding users on Red Hat 5.1. I’ve used various methods to add them to my system via the adduser command and through various X control-panel programs. When I add them, everything seems to go well, and they exist when I look them up after I created them. My problem is that I can’t log in without being root. If I attempt to log in as a user, it will say “login incorrect”, as if I typed in the wrong password or user name, which is not the case. I have tried numerous times and am frustrated since I cannot get any users to work on my system. —Anthony Dipaula, dipaula@udel.edu

You will need to check two files. The first is /etc/passwd. Make sure each user has a valid shell and home directory. Then look at /etc/login.conf. This defines login control settings, and you might have a setting that prevents non-root logins on the console. —Chad Robinson, chadr@brt.com

File Type

Can someone tell me what the hyphen after a file name indicates? Two examples are in /etc: passwd- and group-. Thanks in advance for the answer. —George R. Boyko, grb99@nni.com

These are backups made by the utilities that manage these files. You can most likely delete them safely, but it’s also a good idea to keep them around. Otherwise, if your passwd file ever becomes corrupted, you will be unable to log in, and rebuilding it is always a pain if you don’t have a good copy lying around. —Chad Robinson, chadr@brt.com

Voice/Faxmodem Problem

I have a multi-platform computer running Windows 95, Windows NT 4.0 and SuSE Linux (kernel 2.0.36). My problem is that I don’t know how to install the Plug and Play modem on Linux. With the first two operating systems (Windows 95 and NT), the modem works just fine. I tried many ways of installing the modem using the Isa PNP tools. It recognizes the modem, but I still have trouble setting up the port. I read some of the HOWTOs and they don’t help me much. They say to set up the modem with the setserial command, but I don’t know how to use this command. In the Windows NT 4.0 setup, my modem is installed with the following parameters: COM5, IRQ 07, Input/Output Range 02E8 to 02EF.

Can someone tell me how to set up my modem on Linux? Or how to set up the modem using the setserial command? It is a 3Com US Robotics 56K Voice Faxmodem. —Manuel Enrique, phrotos@email.com

COM5 is usually (not always) a clue that your modem isn’t a modem but a winmodem, which would therefore be useless with anything other than Windows.

Now, if it really is a modem, you should find out which port it is on as far as Linux is concerned (probably ttyS2) with dmesg | grep ttyS right after boot. Then configure the interrupt and the port number like this:

setserial /dev/ttyS2 port 0x3E8 irq 2

substituting the right values for your card. —Marc Merlin, marc@merlins.org

Java Crashing Netscape?

I am somewhat more than a newbie, but when it comes to things I don’t know, I am clueless. I am running on Red Hat 6.0, and Netscape Communicator 4.5. Whenever I go to a Java web site, like linux.com or yahoo.com, Netscape will crash; that is, it will just disappear. If I run Netscape in a terminal ./netscape, it will also disappear whenever I go to a Java site. But in the terminal, it will say “bus error”. What does this mean? I know I enabled Java in my setting, but how can I fix this? —Eric Zabinski, diablo@elnet.com

Netscape has been known to crash for a variety of reasons, many of them linked to Javascript and especially Java. I recommend you try upgrading to Netscape 4.61, or downgrading to Netscape 4.08. —Marc Merlin, marc@merlins.org

PPP and Network Configuration

I recently accomplished my first successful Linux install, Red Hat 5.2. I installed PPP software, but thought network configuration should be done only for NIC-equipped machines, not ones just doing dialup, so I didn’t perform the network configuration at that time.

Although I have subsequently edited a raft of PPP-related files using the HOWTOs, books and the suggestions of an ISP, I don’t get the expected PPP “garbage” (40-character frames with frequent { characters) in response to a pppd command from the command-line prompt. Does this clearly mean that I don’t have PPP support properly installed and need to reinstall or add via a package manager? Or would this also occur with errors in the configuration files (like host.deny or host.allow or …)? —Stephen S. Rinsler, 70353.714@compuserve.com

You should be able to create the PPP connection with netcfg, which you can launch from the control panel that should be there by default when you log in as root and launch X (type control-panel otherwise). You also have the option of using linuxconf to create your PPP connection. —Marc Merlin, marc@merlins.org

Mounting NFS

I need to implement NFS (Network File System) from my Linux host to a WinNT Server for files access. I have Linux Red Hat 5.2 installed on a Pentium 133 MHz and 24MB RAM machine. I also installed the NFS services (client and server). In a server machine, I have Windows NT 4.0. I read the book TCP/IP Illustrated Vol.1 by Richard Stevens (chapter 29 talks about NFS), so I am a beginner of the protocol. When I try to mount an NFS link, the following error appears:

mount: RPC: Port mapper failure - RPC: Unable to send

Can you help me? —Ing. Juan Salazar Velasco, jsalazar@merkafon.com

The easiest way to do this is not with NFS, but with Samba, which you can get at samba.anu.edu.au. By installing Samba on your Linux box, you will be able to use smbclient to access your Windows NT server, and the combination of nmbd and smbd to allow your NT server to access files on your Linux box. This works for printers, too.

NFS services require special configuration in the Windows NT server (and usually additional software), and often aren’t as fast because the native protocols to each type of server (SMB for NT and NFS for UNIX) were designed with somewhat different intentions in mind. In my experience, UNIX emulates SMB better than NT emulates NFS. —Chad Robinson, chadr@brt.com

It’s not clear to me which machine is the NFS server. If it’s Linux, then most likely the portmapper isn’t running. Type:

/etc/rc.d/init.d/portmap restart

Also, make sure that rpc.nfsd and rpc.mountd are running on your machine.

If the server is NT, type:

showmount -e name_of_nt_server

and as long as you don’t get suitable output from it, your NT server isn’t configured correctly. —Marc Merlin, marc@merlins.org

Hard Drive Problems

While trying to install Linux 5.2 from the Linux For Dummies book, I have somehow locked myself and the install program out of it. Once you have partitioned a drive partially for Linux, how do you get back in and straighten out any mess you may have made? The install floppy or the CD-ROM have nothing on them that I can access from the DOS prompt or from the DOS program fdisk, which, by the way, says there is an error reading the disk and won’t let me in. Also, DiskDruid won’t let me back in either. Can you help? —“Budskie”, Budskie@email.msn.com

I would guess that you somehow damaged your partition table, but this is tough to tell without looking further at the drive. You may wish to try a different tool, such as the fdisk program that comes with the Slackware package. It is a more raw tool, and while it may be harder to use, it probably won’t completely stop you from getting to your drive.

I’ve seen problems like this come from misunderstandings about the LBA (logical block addressing) setting in the BIOS for a drive. Unfortunately, without knowing more about what exactly has happened, I can tell you only how to completely wipe out what you’ve done so you can reload your system. (The adage about backups comes to mind here.) If you do go this route, you would want to use a more basic tool (such as the fdisk that ships with Slackware) to remove all of the Linux partitions on your drive in the hopes of recovering your DOS information. Failing that, you could always remove them all and re-install Windows to return to a stable state, then try again. —Chad Robinson, chadr@brt.com


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