linux network if configuration tips

route define: /etc/sysconfig/network-scripts/route-eth1
content:: 172.16.1.0/24 via 172.16.1.1 dev eth1

PXE tips

tftpx policy search order
1: 01-MAC_ADDR
if MAC address of PXE client is 00-15-5D-10-31-08, the PXE policy name must be 01-00-15-5d-10-31-08
Please note, all letters in MAC should be lower case


2: IP (HEX) without dot
if assigned IP address is 192.168.2.89, the PXE policy name must be  C0A80259.
Please note, all letters from the converted IP address bits must be upper case and dot need to be removed from the PXE policy name.

boot option tips:
noacpi
noipv6
lang=en
keymap=us

remote Linux installation on Dell R710 server via PXE through sol

1: enable sol from bios
2: enable ipmi on BMC
3: setup root password for ipmi connection
4: kernel option for pxe label console=tty0 console=ttySx,115200n8
5: boot to text mode --> add " text " to append segment

sol setup on Dell poweredge servers

from BIOS: redirect serial to com2

on ipmi-enabled Linux machine
enable console redirect on kernel
--> modify grub.conf
-->  serial --unit=0 --speed=115200
-->  terminal --timeout=10 serial console
add kernel option --> console=tty0 console=ttyS1,115200n8 

add "ttyS1" to /etc/securetty

and below line to /etc/inittab
co:2345:respawn:/sbin/agetty -h -L 19200 ttyS1 vt100

connect to the Linux server via ipmitool
ipmitool -I lanplus -H IPMI_HOST -U IPMI_ACCOUNT -P IPMI_ACCOUNT_PASSWD sol activate


please note, since I redirect the serial to com2, I have to set kernel option to ttyS1.
If I redirect serial to com1, kernel option for console is supposed to be ttyS0

--init=0 is used to define the initial index for serial port.
when set to 0, ttyS0 is com1. 

intel vPro

install Manageability Developer Tool Kit to configure ME under windows environment

KVM password length must be 8.
Use VNC viewer to connect to the KVM

find command tips

find . -type d ! -perm -o=x -perm -mode --> ambiguous compare
-perm mode --> exactly compare

backup exec tips

-o84  --> find robotic library device id
-o85 --> find robotic library device name
-o103 --> run inventory
-o104 * -a"robotic library device name" --> lock library door
-o105 * -a"robotic library device name" --> unlock library door
-o69 --> get media set id
-o70 --> get media set name and id mapping
-o132 --> list medias which is put in the media set
-o130 --> move media

noise from analog port

boot option for analog port fix

noapic pci=noacpi,usepirqmask

GLIBCXX_3.4.9 cannot be found

1:manually download prerequisites
required package info can be found at contrib/download_prerequisites
2:compile prerequisites with static library (enable static and disable shared )
GMP, MPFR, MPC
3:compile gcc with shared library (please refer options to gcc -v command)
4:use LD_PRELOAD to load proper libstdc++ to start program

debug: strings libstdc++ |grep GLIBC

asterisk channel information

channel information will be truncated by core show channels command
use concise option to retrieve full channel information
core  show channels concise

add user defined variable for agi
Set: variable=xxxx

name resolving issue under vpn connection

relate to dns search order.

http://support.microsoft.com/kb/311218

Const HKLM = &H80000002
sComputer = "."
Set oReg = GetObject("winmgmts:{impersonationLevel=impersonate}!\\" _
& sComputer & "\root\default:StdRegProv") 

sKeyPath = "SYSTEM\CurrentControlSet\Services\Tcpip\Linkage"
sValueName = "Bind"

oReg.GetMultiStringValue HKLM, sKeyPath, sValueName, arValues
arValuesNew = Array()

'patch registry
If UCase(arValues(0)) <> UCase("\device\ndiswanip") Then
ReDim Preserve arValuesNew(0)
arValuesNew(0) = "\Device\NdisWanIp"
For Each objarValues in arValues
If UCase(objarValues) <> UCase("\device\ndiswanip") Then
ReDim Preserve arValuesNew(UBound(arValuesNew)+1)
arValuesNew(UBound(arValuesNew)) = objarValues
End If
Next
End If
If UBound(arValuesNew) <> -1 Then
oReg.SetMultiStringValue HKLM, sKeyPath, sValueName, arValuesNew
End If

grant power control authority to users

GPO registry control
HKLM\SOFTWARE\MICROSOFT\WINDOWS\CURRENTVERSION\CONTROLS FOLDER\POWERCFG
HKLM\SYSTEM\CURRENTCONTROLSET\CONTROL\SESSION MANAGER\POWER

nfsv4

exports option "fsid=0"
https://wiki.archlinux.org/index.php/NFSv4

亦即此share為nfsv4的root
所有其他nfsv4的share必須依賴於此mount point之下
注意:/etc/idmapd.conf設定

run shell command and then display the result on web through asp.net via vb.net

       Dim psi As System.Diagnostics.ProcessStartInfo = New System.Diagnostics.ProcessStartInfo

        psi.FileName = "ipconfig.exe"
        psi.Arguments = " /all"
        psi.UseShellExecute = False
        psi.RedirectStandardInput = True
        psi.RedirectStandardOutput = True

        Dim ps As System.Diagnostics.Process = New System.Diagnostics.Process
        ps.StartInfo = psi
        ps.Start()
        Dim sr As StreamReader = ps.StandardOutput
        Dim aa As String
        While (Not sr.EndOfStream)
            aa = sr.ReadLine
            Response.Write(aa)
            Response.Write("
")
        End While
       ps.Dispose()

specify specific rsync binary

I have 64bits rsync 2.6.9 installed in my environment. When remote site triggers file transfer through rsync to my 32 bits platform, system will complain about rsync binary execution error. The reason is the search order in my environment setup. System looks for rsync binary from /usr/local/bin/ first and then /usr/bin/. In order to get this resolve, you have to specify the rsync path when running rsync command.

session stalled when transfer files between two sites with unstable internet connection

net.core.rmem_default = 524288


net.core.rmem_max = 524288

net.core.wmem_default = 524288

net.core.wmem_max = 524288

net.ipv4.tcp_wmem = 4096 87380 524288

net.ipv4.tcp_rmem = 4096 87380 524288

net.ipv4.tcp_mem = 524288 524288 524288

net.ipv4.tcp_rfc1337 = 1

net.ipv4.ip_no_pmtu_disc = 0

net.ipv4.tcp_sack = 1

net.ipv4.tcp_fack = 1

net.ipv4.tcp_window_scaling = 1

net.ipv4.tcp_timestamps = 1

net.ipv4.tcp_ecn = 0

net.ipv4.route.flush = 1

ref: http://ubuntuforums.org/showthread.php?t=891695

wmi-client for linux

http://pzolee.blogs.balabit.com/2010/09/wmi-client-for-linux/

glibc version issue

in order not to upgrade the whole system to support some specific program, you can pull the required library from the compatible system to desired platform and have LD_PRELOAD or LD_LIBRARY_PATH defined before invoking the process.
in bash
LD_PRELOAD="......" glibc.so target_process

lmgrd去跑vendor daemon會有問題
此時僅需暫時修改預設loader,待lmgrd成功啟用後,在改回預設loader即可

nis map management

nested nfs automount issue
after revising the automap and then push the revised map to clients, nested mount will not appear.

Ans: need to force unmount the map root and restart nfs client
umount -l, fuser -k ....