Networking With Red Hat 8.0

Wednesday Oct 9th 2002 by Carla Schroder

Though much has been made of the popular Linux distribution's enhanced desktop functionality, Red Hat's latest release also includes some new features and fixes helpful to network and system administrators. Carla Schroder reports.

Oldtimer Linux gurus get rather cranky about graphical interfaces. Sissy, bloated, slow. If it is too easy it is suspect, unworthy of the true sysadmin. I think it's nice to have a rather more flexible perspective, and to rejoice in the wealth of choices.

Any flavor of Linux offers superior networking ability and stability. The latest incarnation of Red Hat Linux attempts to make configuration chores a little easier. Sure, it's dead easy to edit a plain text configuration file- when you know which one you need, where it is, available commands and options, and the correct command syntax. Ultimate power and flexibility still lie at the command line- still, why object to tools that make the job easier?

Let's start with installation. Red Hat has added a number of useful options. First is a media test- it will test your disks before starting the installation. I suspect it's merely running a checksum, whatever it is it's a good idea.

Advanced Disk Management
Linux fdisk is a powerful disk-partitioning tool, way more versatile than its Windows cousin, and is available at the beginning of any Linux installation. No need to prepare a hard drive in advance, just pop in the disks and go. Red Hat 8 has gone a couple of steps farther and incorporated the Linux Volume Manager (LVM), and software RAID.

Anytime you're bored, start a debate on the merits of software vs. hardware RAID. Just like dropping a cat in the dog pound. On a modern, powerful machine, Linux RAID performs well. I use it with IDE drives on workstations and low- to- mid-range servers. Not having to set it up after installation is nice.

LVM has traditionally been a bit of a pain to set up. RH8 comes with LVM support compiled into the kernel. Volumes are easily configured with checkboxes and drop-down menus.

Also during installation are several other file system choices: ext2, ext3, and vfat. ext2 is the old workhorse of the Linux world. ext3 adds journaling. ext3 is backwards-compatible to ext2, permitting upgrades of existing filesystems. vfat lets Linux read/write files on FAT and FAT32 filesystems.

Network Configuration
Basic client settings are done during installation. A peeve dear to my heart is the lack of an option to set the hostname. Setting the hostname is not my favorite chore, two files need editing and one command run: /etc/hosts, /etc/sysconfig/network, and the hostname command. Then there is neat, the graphical network administration tool, which has a hostname setting, but it only writes to /etc/hosts.

In RH8, neat is still with us. Still no easy way to set the hostname, but otherwise neat does it all: devices, TCP/IP, routing, DNS, DHCP, the works. And a shiny new feature, Profiles.

Of course a mighty scripting guru would not need such a feature, but I like it. Linux gives tremendous flexibility and control of network configurations and devices, including assigning all manner of aliases, IP addresses, and even changing MAC addresses. Grouping different configurations in profiles makes all that complexity manageable. Laptop users can connect without fuss wherever they happen to be: branch offices, hotels, home; dialup, Ethernet, wireless. Another nice use for this is adding a backup dialup account for users with flaky DSL or cable, as dialup configurations are typically very different from broadband.

And where would we be without VPN? Yep, neat does that too. And wireless, and Token Ring.

Plodding from one machine to the next with a handful of installation disks is one way to get the job done. Another is to automate large installations over the network. The Kickstart Configurator defines and controls installations, whether deploying a large number, or simply creating and saving a highly customized installation. The graphical Kickstart configurator should be sufficient for all but the most finicky admin.

At last Red Hat has eliminated the infamous ipchains gotcha. Red Hat introduced iptables into its distributions way back around 7.0. Unfortunately they also left ipchains in. Probably a good thing to do it that way, for user convenience, but it also created a trap. Always during installation was the option for a basic firewall configuration, which created ipchains rules. The unwary iptables user would often forget, and waste many head-banging hours debugging connectivity problems before remembering that little old ipchains setup. Now it's iptables all the way, hurray.

Type gnome-lokkit as root, or find Lokkit on the menu, to construct or modify basic iptables rules after installation. Remember, every Linux comes with a firewall- take advantage.

Now this is where a graphical tool really shines. Find the 'services' icon on the menu, or in the Start Here box, and every running service is displayed, and all available services. Start, stop, enable/disable at boot, and set runlevels with mere mouse clicks. This is the first thing you should run after installation, as Red Hat insists on installing and running Sendmail, even if you select Postfix during installation. Interestingly, by default Sendmail does not accept network connections from any host other than the local computer, why it is so insistent on being installed is puzzling. Check also for unnecessary services, like pcmcia on a desktop machine. Beats the heck out of messing with a zillion /etc/rc.d files, or futzing with xinetd.

Sharing Is Nice
Another shiny new GUI is for setting up an NFS (network file system) server. Not that it's that hard from the command line, but it's nice to have a list view.

System Log Viewer
My personal favorite. All in one handy viewer: boot, cron, kernel, mail, news, security, system, and XFree86. And best of all, a list of all installed RPMs, which cron updates daily. The viewer is not as feature-full as a more heavy-duty log analyser and parser, but it provides basic filtering and alerts. Another nice feature is a form for moving logfiles around wherever the heck you feel like putting them.

Desktop Linux
Red Hat 8 is aimed at the desktop, though like any Linux distribution, it is endlessly adaptable: server, workstation, firewall, router.... A lot of work went into polish and usability in this edition. Even so, there are still too many redundant menu items. And the default desktop is a bit odd- text editors and terminals are buried deep in the system menus. I don't care how desktoppy a user is, those are basic Linux tools, and should be front and center. Under the hood, many basic components have been significantly upgraded: Apache 2.0, gcc 3.2, Gnome 2, gphoto 2.1.0, and KDE 3.0.3.

Red Hat

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