Best of Technical Support

Questions and Answers
New Install Won't Boot

I attempted to install Red Hat 6.2 on my spare machine. The install ran fine and completed. I removed the disks and rebooted, and I keep getting a nonsystem disk error telling me to replace the disk.

—Tim Dreas,

It seems like either LILO or GRUB, the boot loaders, were never installed correctly. If you made a rescue disk during the installation (of course you did, right?), use it to boot your computer. When you get the root Linux shell prompt (#), type lilo -v, which should attempt to write the boot loader into your hard disk.

—Felipe E. Barousse Boué,

How Do I Remove a User

How do I remove a user from a group? (We deleted the user and now are receiving error messages that there is a permanent fatal error when someone e-mails this group.) How do we correct this?

—Barbara Viola,

I assume you mean mail alias and not a UNIX group. Check out /etc/aliases and remove the user. Then run newaliases.

—Christopher Wingert,

To remove a user from a group, not just from an e-mail alias, use the gpasswd command as root:

gpasswd -d name_of_deleted_user

Take a look at man gpasswd. It gives an explanation and options for other group administrating functions.

—Paul Christensen,

I Have No Static IP Address and I Must SMTP

Is it possible to have an internet mail server with a dial-up connection to an ISP? I know that the IP address of ppp0 may change whenever I establish a new connection with the ISP. The MX records need to point to the mail server; the IP address of the server also must be specified at dewdesigns but will not be valid if or when I get a new connection. Do I need to run DNS locally or can I use the ISP DNS? I recently read an article by Marcel Gagné regarding small-office mail servers, but I feel that I am missing some pieces of the puzzle.

—Daryl E. Murray,

There are ways to have an SMTP server on a dial-up dynamic IP and set up DNS so that it gets updated every time you change your IP address, but trust me, you do not want to go there. Short of running UUCP, which is the correct way to route mail in your case (UUCP is quite old, not well-known by most system administrators and probably not supported by your ISP), you should use Fetchmail to download your mail. If you need to download mail for many accounts, you can have your ISP spool all your mail in one mailbox, download that with Fetchmail, and split it up again, looking at the Envelope-To: field or whatever field in which your ISP stored the original Envelope-To.

—Marc Merlin,

You only can use Fetchmail to download all of your site's mail if your ISP consistently applies an Envelope-To: header to your mail. See the warning at

If you have a dial-up with a static IP address, and your ISP is willing to queue incoming mail for you, you can do an SMTP ETRN when the connection comes up. Sendmail includes a utility to do this.

—Don Marti,



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Thanks. I found the help I needed.