Red Hat 7.2 Guide

IP Address - how to change

System; Network Configuration - Devices; Edit; Protocols; Edit; TCP/IP - note: does not take effect until after system is rebooted.

Starting Services at boot up

Typically I want httpd, wu-ftpd to start at boot up.
Serviceconf is the easiest way to control starting and stopping of services and setting them up to auto start on boot.

"Batch" files

The trick to making a script runnable is to change it's permissions to be executable.
Basics:
#!/bin/sh - this tells the system to use bash to execute/interpret/run this script
$1 - this is a representation of the first passed parameter.

Key file locations

ipchains - /etc/sysconfig/ (changes to ipchains require reboot to take effect)
Webalizer reports - /var/www/html/usage/ - potential security issue (others can view)?
Website files - /var/www/html/
mySQL databases - /var/lib/mysql/

Upgrades in general

Updates can be obtained via "up2date" with a subscription to the Red Hat Network. This is easy and reliable but only good for a single machine.
XFree86 needs to be updated - has a 49 day crash bug as shipped with CDs
Updates can also be obtained via download from http://www.redhat.com/support/errata/

Tripwire Security

Once the system is initially set up (and before a hacker could get at it) set up Tripwire.
Edit /etc/tripwire/twcfg.txt and /etc/tripwire/twpol.txt for any customizations.
Run /etc/tripwire/twinstall.sh as root (this will prompt for two pass phrases)
Initialize the database with /usr/sbin/tripwire - -init
Run a first check with /usr/sbin/tripwire - -check
Tripwire will be run daily by cron, review the file using /usr/sbin/twprint -m -r - -twrfile /var/lib/tripwire/report/<name>.twr

Upgrading the Kernel

• uname -r - gets the kernel version
• /sbin/mkbootdisk kernelversion - makes an emergency boot disk
• rpm -qa | grep kernel - gets list of the kernel packages (what you need to download); "kernel version" is the only package actually needed unless you are going to custom make a new kernel. With full install I have kernel-debug-ver; kernel-headers-ver; kernel-doc-ver; kernel-source-ver;
• rpm -ivh kernel-ver.rpm - installs the new kernel
• for the docs, etc use rpm -Uvh kernel-header-ver.rpm
• update the boot loader (by default install GRUB is selected as the boot loader) - in /boot/grub/grub.conf basically cut and paste the boot section for the old kernel and update the names to reflect your new kernel.

Making a Custom Kernel

• cd /usr/src/linux-2.4
• make mrproper - clean up any mess from previous attempts
• use xconfig to select the options desired in the kernel
• make dep
• make clean
• edit /usr/src/linux-2.4/Makefile and modify the line beginning with EXTRAVERSION; suggested you add the date like "EXTRAVERSION = -0.1.21-jul2001"
• make bzImage
• make modules
• make modules_install
• make install
• update the boot loader

Recovering from the master boot record (MBR) being overwritten

Using an emergency boot disk, boot with linux rescue.

Bugs

Doing a file search of the entire drive can hang RedHat 7.2!