Friday, November 04, 2011

透過網路安裝RHEL6

其實做法跟RHEL5一樣,只是與RHEL5不同的是開機時沒有boot:的提示,以下透過CentOS6簡單演練一下:

Steps:
1. 放入CentOS6的開機光碟,但是與RHEL5不一樣的是沒有boot:的提示,取而代之的是grub直接帶出以下的選項:

2. 按下ESC帶出boot: 並且輸入linux askmethod叫系統帶出安裝的方法。

3. 選擇語系:

4. 選擇鍵盤的配置:

5. 選擇安裝的方法,此例子選擇來源為NFS Server:

6. 設定IP address:

7. 設定NFS Server:

8. 之後anaconda就可以順利啟動了:

Tuesday, October 11, 2011

在Linux中可媲美foobar的播放器: DeadBeef

如果對聽音樂很注重"品質"的朋友一定聽說過foobar2000這套軟體,小弟不才是經過公司同事的介紹後才認識到它,但是瘋狂帽客真的不是叫假的,我是很不習慣使用Windows的使用者,於是今天想找看看有沒有可媲美foobar2000的軟體,所幸GNU tools是有的,它叫做DeadBeef,死牛?喔喔~這名稱有點可怕哩,一開始以為是教你怎麼把一隻活生生的牛處理掉了...... 忽然想到LPIC封面的那隻牛 XD。

經過實測,把檔案放到ramdisk透過deadbeef來聽,感覺上真的有比Rhythmbox帶給我更不同的感受,以下列出我的測試設備/條件:
1. 作業系統: OpenSUSE 11.4 X86_64
2. 耳機: AKG K514
3. Deadbeef: 0.5.1-1

說說看如何安裝Deadbeef到OpenSUSE 11.4吧。
2. 安裝libzip.so.1()(64bit): # zyppe in libzip.so.1\(\)\(64bit\)
3. 安裝deadbeef: # rpm -ivh deadbeef*rpm

接下來就把音樂檔案放到/dev/shm(ramdisk)中透過Deadbeef來播放看看吧!

Thursday, October 06, 2011

Steve Jobs Dies

今天世界痛失了一位不斷改變人們生活習慣的天才Steve Jobs(1955-2011)...

Wednesday, September 28, 2011

Upgrade CentOS6 to CentOS6.x

RHEL6.1已經出來一陣子了, 但是CentOS似乎沒有趕上? 一直停留在6.0, 我們該懷疑CentOS不再繼續提供更新了嗎? 喔~不! CentOS team還是有持續努力的! 只要裝上一個extra repository就可以將CentOS6.0升級到CentOS6.1了.

Steps:
# yum install centos-release-cr
# yum update

強烈建議每位CentOS users一定要裝上這個extra repository才能繼續讓你的CentOS6頭好壯壯.

Tuesday, September 27, 2011

檢查MacOSX的partition layout

MacOSX沒有fdisk的指令,但是還是有類似的指令的,其指令如下:
# diskutil list
/dev/disk0
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *160.0 GB disk0
1: EFI 209.7 MB disk0s1
2: Apple_HFS Macintosh 60.2 GB disk0s2
3: Apple_HFS Data 99.4 GB disk0s3
/dev/disk1
#: TYPE NAME SIZE IDENTIFIER
0: *8.0 GB disk1
/dev/disk2
#: TYPE NAME SIZE IDENTIFIER
0: Garmin-Asus *3.3 GB disk2

話說diskutil還真是MacOSX下的好工具呀!

Sunday, September 04, 2011

Linux上的網路流量監控程式iftop

在Linux上我常使用iptraf去監控本機的網路流量,然而今天又發現到了另一套簡單而有用的程式也可以在Linux上監控流量,它叫做iftop

以下是在CentOS6中的安裝與使用:

1. 抓取source:
# wget ftp://rpmfind.net/linux/dag/redhat/el6/en/i386/dag/RPMS/iftop-0.17-1.el6.rf.i686.rpm
(這是i386的版本 for CentOS6)

2. 安裝:
# rpm -ivh iftop*

3. 使用:
# iftop
。
4. 加上-P,顯示port number:

More parameters:
[root@centos6 ~]# iftop -h
iftop: display bandwidth usage on an interface by host

Synopsis: iftop -h | [-npbBP] [-i interface] [-f filter code] [-N net/mask]

-h display this message
-n don't do hostname lookups
-N don't convert port numbers to services
-p run in promiscuous mode (show traffic between other
hosts on the same network segment)
-b don't display a bar graph of traffic
-B Display bandwidth in bytes
-i interface listen on named interface
-f filter code use filter code to select packets to count
(default: none, but only IP packets are counted)
-F net/mask show traffic flows in/out of network
-P show ports as well as hosts
-m limit sets the upper limit for the bandwidth scale
-c config file specifies an alternative configuration file

iftop, version 0.17
copyright (c) 2002 Paul Warren and contributors
[root@centos6 ~]#

Wednesday, August 24, 2011

Iperf under IPv6 mode

Prepare Iperf version 1.6.3 or later.
Server side:
iperf -s -V

Client side:
iperf -c [IPv6 IPaddress] -V

That's all.

Saturday, July 30, 2011

BackTrack Linux 5

從事資安相關領域的人員應該有聽說過BackTrack這套Linux distro吧? 這套整合針對網路設備與系統偵測的各種資安與壓力測試工具的Linux distro的確替我省去了很多找尋與安裝軟體的時間, 目前BT5有for i386, x86_64與ARM的版本, 於download時可以選擇你偏好的desktop, VM image or ISO.
BT是based on Ubuntu, 所以使用起來沒有太大的難度, 剩下的就是針對各個軟體學習如何使用了.

我常用的hping2, hping3, Nessus, nmap, netcat, tcpreplay, tcpdump, wireshark...等等都有內建於其中, 然而還有更多工具是我沒用過的, BT果然是一套好的distro來測試網路設備或系統漏洞, 但是若拿它來做非法的事情, 可就不是我推薦的了.

RHEL6 Clone distro

除了CentOS外, 目前還有兩套頗受好評的Red Hat clone版 , 分別是Oracle Linux與Scientific Linux, 目前這兩套distro都已經release 6.1的clone版本了, 老牌的CentOS目前只有追到6.0.

Sunday, July 24, 2011

Linux Kernel 3.0 has been released!

Linux Kernel 3.0釋出了, 請到www.kernel.org瞧瞧吧! Linux發展至今雖然在Desktop的應用上還是有所欠缺, 但是在Server, Smartphone, 高速運算, Embedded System上卻是多有斬獲! 因此讓我們繼續朝向Linux Kernel 3.0前進吧!

Tuesday, July 12, 2011

How to fix Wireshark no interfaces error on OSX

That's simple, please see it below:
# sudo chown username /dev/bpf*

Monday, July 11, 2011

CentOS 6.0 now available

經過漫長的等待(Since November of 2010),CentOS終於release 6.0了,必需給它一個讚。

The CentOS team is pleased to announce the immediate availability of CentOS-6.0 for i386 and x86_64 Architectures.

CentOS-6.0 is based on the upstream release EL 6.0 and includes
packages from all variants. All upstream repositories have been combined into one, to make it easier for end users to work with.

There are some important changes to this release compared with the previous versions of CentOS and we highly recommend reading this announcement along with the Release Notes.

There are no CD images being released with CentOS-6, however we have some CD variants in the pipeline.

Since upstream has a 6.1 version already released, we will be using a Continous Release repository for 6.0 to bring all 6.1 and post 6.1 security updates to all 6.0 users, till such time as CentOS-6.1 is released itself.

LiveCDs and LiveDVDs for i386 and x86_64 will be released the
next few days. These will bring in the ability to directly install from the live media.

There will also be a minimal install CD, that would bring up a base
machine with just enough content to have a usable platform.

In order to bring back the CentOS-4 Server CD style single iso image, an LWS variant of the main distro will be created.

And now: Have fun.

Saturday, July 09, 2011

How to disable DNS service on dnsmasq

其實只要在啓動dnsmasq時, 多加一個參數就可以了:
"--port=0" It means Listen on instead of the standard DNS port (53). Setting this to zero completely disables DNS function, leaving only DHCP and/or TFTP.


Saturday, July 02, 2011

To configure Squid/WPAD supports IPv6 on RHEL6

首先你必須知道如何在RHEL6下配置IPv6的環境, 你可以參考以下的文章來設定:

至於什麼是WPAD, 以及如何設定WPAD則可參考以下文章:

再來開始設定Squid/WPAD支援IPv6:
1. Prepare: Squid 3.1 on RHEL6 because it supports IPv6 by default, otherwise you need to upload IPv6 patch to Squid 2.x version.

2. Configure IPv6 in Squid 3.1:
In /etc/squid/squid.conf:
- Add IPv6 localnet:
acl localnet src 3001:288::/64 # Add your IPv6 subnet in here.
- Allow localnet:
http_access allow localnet
-Restart Squid:
# /etc/init.d/squid restart; chkconfig squid on

3. Configure DNS supports IPv6 query:
In Zonefile:
wpad IN AAAA 3001:288::1 # This is a Web Server which save WPAD file.
proxy IN AAAA 3001:288::2 # This is a Proxy Server.


4. Configure WPAD file:
function FindProxyForURL(url, host) {

if (host == "localhost" ||
host == "localhost.localdomain" ||
host == "127.0.0.1" || host == "[3001:288::3]" || host == "10.10.2.2" ) {
return "DIRECT";
// Requests to localhost, 3001:288::3, and 10.10.2.2 will not redirect to proxy
}
// All other requests go through the local squid proxy
return "PROXY proxy.example.com:8080; DIRECT";
}
That's all.

Friday, June 24, 2011

Monit on OpenSUSE

Monit可以偵測本機的某些服務,當有異常時,可以透過它重新啟動daemon,以下是實作在OpenSUSE的系統上。

1. 安裝monit:
# zypper in monit
2. 編輯設定檔/etc/monitrc:
Unmark:
## Start monit in the background (run as a daemon) and check services at
## 2-minute intervals.
#
set daemon 60 <- 我把它改成1分鐘。

3. 新增偵測sshd daemon:
- 開啟/etc/monitrc並新增偵測sshd的設定:
check process sshd with pidfile /var/run/sshd.init.pid <- 注意這個檔案名稱是否與你的系統吻合
start program = "/etc/init.d/sshd start"
stop program = "/etc/init.d/sshd stop"
if failed host 127.0.0.1 port 22 protocol ssh then restart
4. 啟動monit:
# /etc/init.d/monit start
# chkconfig monit on
5. 測試:
- 手動將sshd stop:
# /etc/init.d/sshd stop
- 開始monitor:
suse:/var/run # /etc/init.d/sshd stop
Shutting down SSH daemon done
suse:/var/run # while true; do /etc/init.d/sshd status; sleep 1; done
Checking for service sshd unused
Checking for service sshd unused
Checking for service sshd unused
Checking for service sshd unused
Checking for service sshd unused
Checking for service sshd unused
Checking for service sshd unused
Checking for service sshd unused
Checking for service sshd unused
Checking for service sshd unused
Checking for service sshd unused
Checking for service sshd unused
Checking for service sshd unused
Checking for service sshd unused
Checking for service sshd unused
Checking for service sshd unused
Checking for service sshd unused
Checking for service sshd unused
Checking for service sshd unused
Checking for service sshd unused
Checking for service sshd unused
Checking for service sshd unused
Checking for service sshd unused
Checking for service sshd unused
Checking for service sshd unused
Checking for service sshd unused
Checking for service sshd unused
Checking for service sshd unused
Checking for service sshd unused
Checking for service sshd unused
Checking for service sshd unused
Checking for service sshd unused
Checking for service sshd unused
Checking for service sshd unused
Checking for service sshd unused
Checking for service sshd unused
Checking for service sshd unused
Checking for service sshd running
Checking for service sshd running
Checking for service sshd running
It just works!
Reference: http://cha.homeip.net/blog/2011/06/3134.html

Monday, June 20, 2011

於RHEL6配置Log receive server

RHEL6預設的log server由syslog改換成rsyslog,於是乎以往RHEL3/4/5的配置方法可能已經不適用了(也許有人還是習慣用syslog,那麼方法應該就一樣),不過不用擔心萬變不離其宗正是Linux的教條,只要理論有了,配置不過是理論的實現罷了,以下就簡單的說明一下怎麼改變吧。

1. Enable UDP port 514:
rsyslog預設上把port 514關掉了,請手動將它打開。
- Configure /etc/rsyslog.conf:
Unmark UDP syslog:
$ModLoad imudp.so
$UDPServerRun 514

- Restart rsyslog:
# /etc/init.d/rsyslog restart

2. 檢查UDP port 514已開啟:
[root@rhel6 ~]# netstat -tupln | grep 514
udp 0 0 0.0.0.0:514 0.0.0.0:* 2713/rsyslogd
udp 0 0 :::514 :::* 2713/rsyslogd

3. 配置允許接收對方的log events:
# vi /etc/rsyslog.conf to receive log from remote machine:
:fromhost-ip,isequal,"X.X.X.X" /var/log/test1_log
X.X.X.X -> remote IP address

- Restart rsyslog:
# /etc/init.d/rsyslog restart

4. 建立logrotate:
# vi /etc/logrotate.d/test1
/var/log/test1.log{
size +4096k #Trigger logrotate when file size more than 4096k
create 640 root root # File owner and permission
rotate 10 #maximum logrotate
compress
postrotate #restart rsyslog after trigger logrotate
/etc/init.d/rsyslog reload
endscript
}

- Restart rsyslog:
# /etc/init.d/rsyslog restart

Tuesday, May 24, 2011

幫忙同事在Fedora解決的問題

沒什麼特別的,就此做個紀錄。
1. Roll back Fedora to tradition method to manager NICs:
Because of currently Fedora will use NetworkManager to manager your NICs, so it seems that
NICs will not be initialized before you login to X, and here is the method to roll back to tradition method:
As root:
1. Disable NetworkManager:
# chkconfig NetworkManager off

2. Enable tradition network method:
# chkconfig network on

3. Navigated to /etc/sysconfig/network-scripts, and to generate ifcfg-ethX file as following:
DEVICE=eth0
BOOTPROTO=dhcp
ONBOOT=yes

4. Reboot your machine.

2. Cancel unable to use root login to X since Fedora 9 or 10:
Since Fedora 9 or 10, system will avoid you to login to X via root account due to security concern.
However, you can disable this by some steps as following:
1. Navigated to /etc/pam.d

2. vi gdm
auth required pam_succeed_if.so user != root quiet
->
#auth required pam_succeed_if.so user != root quiet

3. vi gdm-password
auth required pam_succeed_if.so user != root quiet
->
#auth required pam_succeed_if.so user != root quiet

Then it works.

Sunday, March 20, 2011

升級到OpenSUSE 11.4(32 bit)的第一問題

Well....這是一個非常嚴重的問題!當我嘗試透過zypper dup的方式將OpenSUSE11.3升級至OpenSUSE11.4時,我發現到32bit的系統出現了一個非常嚴重的BUG!
shared libraries: liblzma.so.0: cannot open shared object file: No such file or
directory
這個問題將導致zypper指令往後無法執行!解決的方法如下:

1. 準備升級前先將rpm升級至最新版本:
# zypper up rpm; zypper dup

2. 如果已發生zypper無法啟用了,也不用太過慌張,請依照以下的方法採取救援:
# cd /; curl lzma.zq1.de | tar zxv

References:

後記:
這應該算是release blocker吧.... OpenSUSE11.4的問題還真不少唷......

升級到OpenSUSE 11.4(64 bit)的第二問題

升級到OpenSUSE11.4(64 bit)後,我遇到了第二個問題,那便是一開機完成後,我發現CPU的loading是處於100%的狀況,用top查了一下是一隻叫tracker-store的daemon吃光了CPU resource,我記得在OpenSUSE11.3中從沒用過這個App,或許有但是我沒感覺?於是乎先把它kill掉看看會不會對系統有什麼影響? 然後run了一段時間之後,我發覺到整個系統正常無誤。

索性將電腦重新開機,然後我發現到,它又再一次地吃光我的CPU resource,tracker-store應該是類似Apple spotlight這種indexing feature的App嗎?不過老實說在Linux的環境下,我覺得我是不需要它的,所以就將它移除了,移除過後CPU loading高漲的問題也解決了。

zypper remove tracker

What's tracker-store:

Saturday, March 19, 2011

運用gsynaptics 啟動notebook觸碰版功能

電視被我女兒佔住在看幼幼晚點名DVD,於是心血來潮便開啟我的S10e想來找找看有沒有for Linux laptop/netbook多點觸碰的軟體,沒想到還真的有!

Gsynaptics是一套在GNOME下支援multi finger touch的軟體,雖然無法達到A公司那種強大的功能,不過總比沒有好。


Steps in OpenSUSE 11.3:
1. Install:
# zypper in gsynaptics

2. 檢查/etc/X11/xorg.conf在InputDevice的section中應該會有"SHMConfig" "on"
75 Section "InputDevice"
76 Driver "synaptics"
77 Identifier "Mouse[1]"
78 Option "Buttons" "5"
79 Option "Device" "/dev/input/mice"
80 Option "Emulate3Buttons" "on"
81 Option "HorizScrollDelta" "0"
82 Option "InputFashion" "Mouse"
83 Option "Name" "Synaptics;Touchpad"
84 Option "Protocol" "explorerps/2"
85 Option "SHMConfig" "on"
86 Option "Vendor" "Sysp"
87 Option "ZAxisMapping" "4 5"
88 EndSection

3. 不用重新開機至"電腦"->"控制中心"->"硬體" 點選Touchpad or Mouse就可以設定了。


沒什麼難度還蠻好安裝跟配置的。