Difference between revisions of "Category:Linux troubleshooting"

Revision as of 00:13, 15 October 2006

This category will contain a collection of articles on troubleshooting Linux. It will be highly biased towards SuSE Linux (version 10.1 or later), as that is my primary OS. I am also using a 64-bit (x86_64) kernel, so my articles will also be biased towards these systems.

System information

% cat /proc/cpuinfo
% cat /proc/partitions
% cat /proc/meminfo
% cat /etc/X11/xorg.conf

% uname -a  # system architecture
% grep ^VERSION /etc/SuSE-release  # To see which SuSE Linux version you are using
% pstree

% getconf   # print system configuration variables
% getconfig # get configuration information for the Xorg server
% systool   # view system device information by bus, class, and topology

% cat /proc/scsi/scsi
WDC WD2000JD-22H Rev: 08.0
SATA-I, 200 GB, 150 MB/s, 8 MB Cache, 7200 RPM

% cat /proc/net/arp
IP address       HW type     Flags       HW address            Mask     Device
192.168.xxx.xxx  0x1         0x2         00:00:00:00:00:00     *        eth0
192.168.xxx.xxx  0x1         0x2         00:00:00:00:00:00     *        eth0

Sound problems

Note, my sound card specs: Intel Corporation 82801EB/ER (ICH5/ICH5R) AC'97 Audio Controller

• Un-mute PCM sound
• Check the following:

% lsmod | grep snd
% cat /etc/modprobe.conf
% vi /etc/modprobe.d/sound

(change "snd-intel8x0" to "snd_intel8x0")

% ./sbin/lspci

(list sound specs / Multimedia audio controller)

% modprobe snd-via82xx

Hacked?

• Check for failed logins in: /var/log/messages
• Regularly monitor:

  • grep -i failed /var/log/auth.log

  • last
  • w and/or who
  • uptime
• Verify that /etc/passwd hasn't changed.
• Check fuser for ports.
• Search for portscans in server report.
• Check for weird processing hogging the CPU.
• Use fail2ban, DenyHosts, etc.

Notes

• pstree — display a tree of processes
• lsmod — program to show the status of modules in the Linux Kernel
• modprobe — program to add and remove modules from the Linux Kernel
• netstat — Print network connections, routing tables, interface statistics, masquerade connections, and multicast memberships
• lspci — list all PCI devices
• more /usr/share/pci.ids — A list of all known PCI ID's (vendors, devices, classes, and subclasses). Maintained at The Linux PCI ID Repository, use the update-pciids utility to download the most recent version.

External links

• SuSE wiki
• How to get specific programs to run under Dapper Drake 64-bit edition