Linux reset password

-

reset root password
1. when you are in the system, modify /etc/passwd, delete the "x" in root line to clean the password;
2. when you are not in the system, enter the single mode to reset or clean password of root;
When you reset password got error, you may need to close the SElinux: setenforce 0
3. when you are not in the system and not have grub password, use cd to start system.
inpu: linux rescure
after it the hard disk system will be mount below: /mnt/sysimage
change the /etc/passwd and /etc/grub/grub.conf file to clean the password of root;
Linux启动：/boot/grub/grub.conf
去掉菜单的背景色：在"splashimage=(hd0,0)/grub/splash.xpm.gz"行前加"#"
手工模拟正常启动：
1. 重启RHEL;
2. 进入选择启动菜单模式，输入"c“，进入command-line
3. 输入：root (hd0,0)回车
4. 输入：cat / 制表键（Tab）查看是否有vmlinuz-......
5. 输入：root (hd0,1)回车
6. 输入：cat / 制表键（Tab）查看是否有/boot；如果没有继续找
5. 输入：root (hd0,2)回车（可以通过输入"root (hd0,制表键"来查看所有的Filesystem列表）
6. 输入：cat / 制表键（Tab）查看是否有/boot；如果没有继续找
7.例如找到在(hd0,7)，输入如下内容：
root (hd0,0)回车
kernel / vm制表键 ro root=/dev/hda8回车
initrd / init制表键回车
boot回车
配置单用户模式：
修改文件：/boot/grub/grub.conf
原内容：
default=0
timeout=5
splashimage=(hd0,0)/grub/splash.xpm.gz
hiddenmenu
title Red Hat Enterprise Linux Server (2.6.18-128.el5)
 root (hd0,0)
 kernel /vmlinuz-2.6.18-128.el5 ro root=LABEL=/ rhgb quiet
 initrd /initrd-2.6.18-128.el5.img修改后：
default=0
timeout=5
splashimage=(hd0,0)/grub/splash.xpm.gz
hiddenmenu
title Red Hat Enterprise Linux Server (2.6.18-128.el5)
 root (hd0,0)
 kernel /vmlinuz-2.6.18-128.el5 ro root=LABEL=/ rhgb quiet
 initrd /initrd-2.6.18-128.el5.img
title Single mode
 root (hd0,0)
 kernel /vmlinuz-2.6.18-128.el5 ro root=LABEL=/ single
 initrd /initrd-2.6.18-128.el5.img
修改后，重启是需按任意键进入菜单，选择单用户模式
单用户模式，主要用来修改root密码
从单用户模式进入普通模式：init 3
set grub password：
change file：/boot/grub/grub.conf
在"title"行前面加入：password 1111
重启后，就需要输入密码才能登录。
但是这是明文密码，保存不安全。
可以使用加密命令： grub-md5-crypt
将密文复制到grub.conf中
例如：password --md5 <密文>

Comments

Post a Comment

Popular posts from this blog

Nginx Proxy & Load Balance & LNMP

-
Nginx Proxy Service E-commerce website Server 1: provide image request response (  apache / nginx ) Server 2: provide dynamic request response ( php-fpm / apache-php ) Server 3: provide static request response ( apache / nginx ) Server 4: provide data request response ( mysql ) It need one additional nginx server 1. Install nginx 2. proxy to specific server Example location / {      proxy_pass http://192.168.199.187:80/; } location /bbs/ {      proxy_pass http://192.168.199.187:80/bbs/; } location ~* \.(jpg|png|gif)$  {      proxy_pass http://172.16.100.7; } Enhance the log information and specific the hostname location / {      proxy_pass  http://192.168.199.187:80/;      proxy_set_header <parameter name>  $host;  (client requst the hostname )      proxy_set_header <parameter name> $remote_addr; ...
Read more

Linux RHCE Preparation

-
RHCE 1. Start classroom-rh254 2. Set environment: yum install ./examrhce-0.0.1-l.el7.x86_64.rpm -y 3. Start server-rh254 4. Set lab environment: lab examrhce setup 5. Start desktop-rh254 6.  Set lab environment: lab examrhce setup 7. Check result: lab examrhcsa grade 1. Set Selinux A. Change config file: vim /etc/sysconfig/selinux B. Temporary set selinux: setenforce 1 C. Check selinux: getenforce If it used to be disabled, you need to restart to change to enforcing.  2. SSH Access Setting A. Disable the firewall for RHEL 6 i. systemctl mask iptables; ii. systemctl mask ip6tables; iii systemctl mask ebtable.service B. Start the firewall for RHEL 7 i. systemctl enable firewalld ii. systemctl start firewalld C. Set firewall rule i. Allow ssh: firewall-cmd --permanent --add-service=ssh ii. Block subnet for ssh: firewall-cmd --permanent --add-rich-rul='rule family=ipv4 source address=172.17.10.0/24 service=ssh reject' D. Reloa...
Read more

Snort+barnyard2+Snorby CentOS 6.5_64 Installation

-
#download packages: daq-2.0.2.tar.gz ImageMagicK-6.8.9-8.tar.gz oinkmaster-2.0.tar.gz ruby-1.9.3-p547.tar.gz snort-2.9.6.2.tar.gz snortrules-snapshot-2962.tar.gz MySQL-server-5.5.40-1.rhel5.x86_64.rpm MySQL-client-5.6.21-1.rhel5.x86_64.rpm MySQL-devel-5.6.21-1.rhel5.x86_64.rpm MySQL-shared-5.6.21-1.rhel5.x86_64.rpm epel-release-6-8.noarch.rpm barnyard2-2.1.13.tar.gz #install yum package rpm -ivh epel-release-6-8.noarch.rpm yum install gcc-c++ patch readline readline-devel zlib zlib-devel flex git yum install libyaml-devel libffi-devel openssl-devel make  yum install bzip2 autoconf automake libtool bison iconv-devel libxml2-devel libxslt  yum install gcc g++ build-essential libssl-devel libreadline5-devel zlib1g-devel linux-headers-generic libsqlite3-devel libxslt-devel curl-devel sqlite-devel yum --enablerepo=epel install jasper jasper-libs jasper-devel #Mysql install yum remove mysql mysql-libs rpm -ivh MySQL-server-5.5.40-1.rh...
Read more