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2009年4月28日

RedHat Linux操作系统修改时区的方法
Most modern Linux distributions have user-friendly programs to set the timezone, often accesible through the program menus or right-clicking the clock in a desktop environment such as KDE or GNOME. Failing that it’s possible to manually change the system timezone in Linux in a few short steps.
It’s possible to change the system timezone in Linux in a few short steps.
Steps
1. Logged in as root, check which timezone your machine is currently using by executing `date`. You’ll see something like “Mon 17 Jan 2005 12:15:08 PM PST -0.461203 seconds”, PST in this case is the current timezone.
2. Change to the directory to /usr/share/zoneinfo, here you will find a list of time zone regions. Choose the most appropriate region, if you live in Canada or the US this directory is the “Americas” directory.
3. If you wish, backup the previous timezone configuration by copying it to a different location. Such as `mv /etc/localtime /etc/localtime-old`.
4. Create a symbolic link from the appropiate timezone to /etc/localtime. Example: `ln -s /usr/share/zoneinfo/Europe/Amsterdam /etc/localtime`.
5. If you have the utility rdate, update the current system time by executing `/usr/bin/rdate -s time.nist.gov`. (This step can be skip!)
6. Set the ZONE entry in the file /etc/sysconfig/clock file (e.g. “America/Los_Angeles”)
7. Set the hardware clock by executing: ` /sbin/hwclock –systohc`
Tips
· On some versions of RedHat Linux, Slackware, Gentoo, SuSE, Debian, Ubuntu, and anything else that is “normal”, the command to display and change the time is ‘date’, not ‘clock’
· On RedHat Linux there is a utility called “Setup” that allows one to select the timezone from a list, but you must have installed the ‘redhat-config-date’ package.
Warnings
· Some applications (such as PHP) have separate timezone settings from the system timezone.
· On some systems, /etc/localtime is actually a symlink to the appropriate file under the /usr/share/zoneinfo directory (rather than a copy of that file).
· On some systems, there is a system utility provided that will prompt for the correct timezone and make the proper changes to the system configuration. For example,Debianprovides the “tzsetup” utility.
Here is an example of changing the timezone: (Logged in as root)
In order to manually change the timezone, you can edit the /etc/sysconfig/clockfile and then make a new soft link to /etc/localtime. Here is an example of changing the timezone manually to “America/Denver”:
1. Select the appropriate time zone from the /usr/share/zoneinfo directory. Time zone names are relative to that directory. In this case, we will select “America/Denver”
2. Edit the /etc/sysconfig/clocktext file so that it looks like this:
ZONE=”America/Denver”
UTC=true
ARC=false
Of course, this assumes that your hardware clock is running UTC time…
3. Delete the following file: /etc/localtime (backup it when you need it !)
4. Create a new soft link for /etc/localtime. Here is an example of step 3 and step 4:
# cd /etc
# ls -al localtime
lrwxrwxrwx 1 root root 39 Mar 28 07:00 localtime -> /usr/share/zoneinfo/America/Los_Angeles
# rm /etc/localtime
# ln -s /usr/share/zoneinfo/America/Denver /etc/localtime
# ls -al localtime
lrwxrwxrwx 1 root root 34 Mar 28 08:59 localtime -> /usr/share/zoneinfo/America/Denver
# date
Fri Mar 28 09:00:04 MST 2003


针对中国时区,修改操作如下
1.   修改文件 /etc/sysconfig/clock内容:
ZONE=Asia/Shanghai
UTC=false
ARC=false
2.     rm /etc/localtime
ln -sf /usr/share/zoneinfo/Asia/Shanghai /etc/localtime
还有其他方法修改时区,不过是基于图形化界面的命令: tzselect 、 timeconfig
本文为镜像,原贴在此:http://www.btk4ever.com/?p=10443

posted @ 2009-04-28 09:35 生活在别处 阅读(2147) | 评论 (0)编辑 收藏

朋友搬到个新地方,没有宽带了,但是能收到些加密的无线网络,挺想蹭网的,本人由于是所谓“挨踢”人士,自当义不容辞出手相助。

我也只是想了解下WEP破解这事,目的也只是提醒大家一下要加强无线网络安全,千万不要干啥非法的事情,当然有本事的话,就把屁股擦干净。

其实前两年我就知道WEP加密是极不安全的,而且也出于好奇做过密钥破解的尝试,但是由于破解软件特别挑网卡,结果自然就是半途而废了。这次到网上 再度查了点相关资料,发现这事情已然变得相当的简单了,基本上只需要 BackTrack3 就可以搞定了。Backtrack 是一个黑客操作系统,其实也算是一个linux的黑客版,主要是安装了很多实用的软件和黑客工具,偏向于安全侵入方面的。

我是下载了一个BackTrack3 的usb版本,并且下了最新的扫描工具spoonwep2,系统自带的是spoonwep也能用,但是据说新版更好使,更方面。整个过程挺简单的,机器设 置成usb可引导启动,然后启动进入usb上的BackTrack系统,都是图形界面的,打开spoonwep2工具,扫描周围的无线信号,选择信号强 的,有客户端连接,并且DATA包比较多的信号来破解吧,这样应该可以快点,据说XX分钟就能破解了。没有客户端连接的无线信号,据说有些AP也是同样可 以破解的,无非是攻击方式的变化以及花费的时间更长而已。

我的经历是,晚上10点多开始破一个无线信号,等了一个多小时,进度开始变缓慢,因为本来连着的两个客户端下线了,估计困搞去了…,很无奈,我也不 能傻等,只得也睡觉去了。第二天早上起来,1o点多的时候,才抓满了要求的数据包,整个密钥破解过程倒是瞬间完成,然后我看到的密码是”1111111″ ,囧 rz,看来设无线密码的人都很懒。这个过程还是挺漫长的,可能是没选择对正确的攻击方式,导致数据包获取的过程很长。假如有客户端在BT下载,估计快很 多,要是只是qq聊天,那就要耗很久了。不过整个过程,已经相当的傻瓜化了。

这事也不能说的太细,想了解详细的人,网上查去吧,顺便提供一个教程

至于如何加强无线安全,有这么几点(网上找的)

如果你需要你的AP很难被破解,建议:
1)用WPA 加密方式,并且使用不可能被字典猜到的密码,目前还是基本可靠的
2)如果只支持 WEP加密,那么,尽量考虑用隐藏 SSID的方式,这样可以增加破解难度
3)如果只支持 WEP加密,那么,可以考虑使用中文名字作为SSID,这样基本问题不大。
4)一般破解时候,大家都会选择常用的频道,例如 6频道, 第三步显示频道的时候,你的AP也会被列出来,那么第一个目标失败的时候,黑客往往会选择第二个容易下手的目标, 但是如果你选择了8、 4、这些奇怪的频道,那么狠客往往懒得重新进入该频道的监控模式,你就可以逃过一劫。不过, 某些廉价AP,往往对6 频道做了优化,这个频道信号最强….这就没办法了。
5)有空换换你的密码:)

还有其他几点也可以做,如减低信号、关闭DHCP、MAC地址绑定,当然这些措施也只是增加难度而已。

最后提一下,蹭网是有风险的,无线信号不加密的,人家未必就是大善人或者菜鸟,而且还有人专门钓鱼的,加大信号,设置简单密码,专门等蹭网的人来,数据包一抓,等着被玩吧。

本文为镜像,原贴在此:http://www.btk4ever.com/?p=10423

posted @ 2009-04-28 09:33 生活在别处 阅读(1182) | 评论 (0)编辑 收藏