Liunx基礎優化配置
阿新 • • 發佈：2018-01-23
uuid routing disabled req 文件 gpo 自啟 p s 1.8
1： 為系統添加操作用戶，並授予sudo權限
[root@localhost ~]# groupadd cai [root@localhost ~]# useradd cai -g cai [root@localhost ~]# passwd cai 更改用戶 cai 的密碼 。 新的 密碼： 無效的密碼： 過於簡單化/系統化 無效的密碼： 過於簡單 重新輸入新的 密碼： passwd： 所有的身份驗證令牌已經成功更新。 [root@localhost ~]# su - cai
sudo的配置文件在/etc/sudoers下面，不過是只讀文件。想要修改使用“visudo”命令。
用戶名 可登錄的終端 具體命令（使用絕對路徑，which查看）
cairui ALL=(ALL) /usr/sbin/useradd
2： 配置Yum源為國內源（在我的其他博客中專門有一篇介紹，此處不寫了）
3： 關閉防火墻（iptables）和Selinux
（1）因為防火墻和selinux的設置很麻煩，而且需要大量的時間去搞，所以索性就關掉。
臨時關閉防火墻：（可以查看狀態，重啟，關閉，打開）
[root@localhost ~]# /etc/init.d/iptables
Usage: iptables {start|stop|reload|restart|condrestart|status|panic|save}
永久關閉防火墻：（關閉開機自啟）
[root@localhost ~]# chkconfig iptables off
查看iptables開機狀態：
[root@localhost ~]# chkconfig --list | grep iptables iptables 0:關閉 1:關閉 2:關閉 3:關閉 4:關閉 5:關閉 6:關閉
（2）關閉selinux
[root@localhost ~]# vim /etc/selinux/config # This file controls the state of SELinux on the system. # SELINUX= can take one of these three values: # enforcing - SELinux security policy is enforced. # permissive - SELinux prints warnings instead of enforcing. # disabled - No SELinux policy is loaded. #SELINUX=enforcing SELINUX=disabled 修改為disabled # SELINUXTYPE= can take one of these two values: # targeted - Targeted processes are protected, # mls - Multi Level Security protection. SELINUXTYPE=targeted
4： 修改ssh服務的默認配置
修改之前先備份默認的配置：
[root@localhost ~]# cp /etc/ssh/sshd_config /etc/ssh/sshd_config.backup
再修改
[root@localhost ~]# vim /etc/ssh/sshd_config # $OpenBSD: sshd_config,v 1.80 2008/07/02 02:24:18 djm Exp $ # This is the sshd server system-wide configuration file. See # sshd_config(5) for more information. # This sshd was compiled with PATH=/usr/local/bin:/bin:/usr/bin # The strategy used for options in the default sshd_config shipped with # OpenSSH is to specify options with their default value where # possible, but leave them commented. Uncommented options change a # default value. #Port 22 Port 52000 修改Linux默認連接端口 #AddressFamily any #ListenAddress 0.0.0.0 #ListenAddress :: # Disable legacy (protocol version 1) support in the server for new # installations. In future the default will change to require explicit # activation of protocol 1 Protocol 2 # HostKey for protocol version 1 #HostKey /etc/ssh/ssh_host_key # HostKeys for protocol version 2 #HostKey /etc/ssh/ssh_host_rsa_key #HostKey /etc/ssh/ssh_host_dsa_key # Lifetime and size of ephemeral version 1 server key #KeyRegenerationInterval 1h #ServerKeyBits 1024 # Logging # obsoletes QuietMode and FascistLogging #SyslogFacility AUTH SyslogFacility AUTHPRIV #LogLevel INFO # Authentication: #LoginGraceTime 2m #PermitRootLogin yes PermitRootLogin no #不允許root用戶登錄（因為每個人都知道root能夠登錄） #StrictModes yes #MaxAuthTries 6 #MaxSessions 10 #RSAAuthentication yes #PubkeyAuthentication yes #AuthorizedKeysFile .ssh/authorized_keys #AuthorizedKeysCommand none #AuthorizedKeysCommandRunAs nobody # For this to work you will also need host keys in /etc/ssh/ssh_known_hosts #RhostsRSAAuthentication no # similar for protocol version 2 #HostbasedAuthentication no # Change to yes if you don‘t trust ~/.ssh/known_hosts for # RhostsRSAAuthentication and HostbasedAuthentication #IgnoreUserKnownHosts no # Don‘t read the user‘s ~/.rhosts and ~/.shosts files #IgnoreRhosts yes # To disable tunneled clear text passwords, change to no here! #PasswordAuthentication yes #PermitEmptyPasswords no PasswordAuthentication yes # Change to no to disable s/key passwords #ChallengeResponseAuthentication yes ChallengeResponseAuthentication no # Kerberos options #KerberosAuthentication no #KerberosOrLocalPasswd yes #KerberosTicketCleanup yes #KerberosGetAFSToken no #KerberosUseKuserok yes # GSSAPI options #GSSAPIAuthentication no GSSAPIAuthentication yes #GSSAPICleanupCredentials yes GSSAPICleanupCredentials yes #GSSAPIStrictAcceptorCheck yes #GSSAPIKeyExchange no # Set this to ‘yes‘ to enable PAM authentication, account processing, # and session processing. If this is enabled, PAM authentication will # be allowed through the ChallengeResponseAuthentication and # PasswordAuthentication. Depending on your PAM configuration, # PAM authentication via ChallengeResponseAuthentication may bypass # the setting of "PermitRootLogin without-password". # If you just want the PAM account and session checks to run without # PAM authentication, then enable this but set PasswordAuthentication # and ChallengeResponseAuthentication to ‘no‘. #UsePAM no UsePAM yes # Accept locale-related environment variables AcceptEnv LANG LC_CTYPE LC_NUMERIC LC_TIME LC_COLLATE LC_MONETARY LC_MESSAGES AcceptEnv LC_PAPER LC_NAME LC_ADDRESS LC_TELEPHONE LC_MEASUREMENT AcceptEnv LC_IDENTIFICATION LC_ALL LANGUAGE AcceptEnv XMODIFIERS #AllowAgentForwarding yes #AllowTcpForwarding yes #GatewayPorts no #X11Forwarding no X11Forwarding yes #X11DisplayOffset 10 #X11UseLocalhost yes #PrintMotd yes #PrintLastLog yes #TCPKeepAlive yes #UseLogin no #UsePrivilegeSeparation yes #PermitUserEnvironment no #Compression delayed #ClientAliveInterval 0 #ClientAliveCountMax 3 #ShowPatchLevel no #UseDNS yes UseDNS no #不使用DNS #PidFile /var/run/sshd.pid #MaxStartups 10:30:100 #PermitTunnel no #ChrootDirectory none # no default banner path #Banner none # override default of no subsystems Subsystem sftp /usr/libexec/openssh/sftp-server # Example of overriding settings on a per-user basis #Match User anoncvs # X11Forwarding no # AllowTcpForwarding no # ForceCommand cvs server
修改完之後重啟：
[root@localhost ~]# /etc/init.d/sshd
用法： /etc/init.d/sshd {start|stop|restart|reload|force-reload|condrestart|try-restart|status}
5： 系統內核優化
[root@localhost ~]# cat /etc/sysctl.conf # Kernel sysctl configuration file for Red Hat Linux # # For binary values, 0 is disabled, 1 is enabled. See sysctl(8) and # sysctl.conf(5) for more details. # # Use ‘/sbin/sysctl -a‘ to list all possible parameters. # Controls IP packet forwarding net.ipv4.ip_forward = 0 # Controls source route verification net.ipv4.conf.default.rp_filter = 1 # Do not accept source routing net.ipv4.conf.default.accept_source_route = 0 # Controls the System Request debugging functionality of the kernel kernel.sysrq = 0 # Controls whether core dumps will append the PID to the core filename. # Useful for debugging multi-threaded applications. kernel.core_uses_pid = 1 # Controls the use of TCP syncookies net.ipv4.tcp_syncookies = 1 # Controls the default maxmimum size of a mesage queue kernel.msgmnb = 65536 # Controls the maximum size of a message, in bytes kernel.msgmax = 65536 # Controls the maximum shared segment size, in bytes kernel.shmmax = 68719476736 # Controls the maximum number of shared memory segments, in pages kernel.shmall = 4294967296 # 下面是內核調優參數 net.ipv4.tcp_syn_retries = 1 net.ipv4.tcp_synack_retries = 1 net.ipv4.tcp_keepalive_time = 600 net.ipv4.tcp_keepalive_probes = 3 net.ipv4.tcp_keepalive_intvl =15 net.ipv4.tcp_retries2 = 5 net.ipv4.tcp_fin_timeout = 2 net.ipv4.tcp_max_tw_buckets = 36000 net.ipv4.tcp_tw_recycle = 1 net.ipv4.tcp_tw_reuse = 1 net.ipv4.tcp_max_orphans = 32768 net.ipv4.tcp_syncookies = 1 net.ipv4.tcp_max_syn_backlog = 16384 net.ipv4.tcp_wmem = 8192 131072 16777216 net.ipv4.tcp_rmem = 32768 131072 16777216 net.ipv4.tcp_mem = 786432 1048576 1572864 net.ipv4.ip_local_port_range = 1024 65000 net.ipv4.ip_conntrack_max = 65536 net.ipv4.netfilter.ip_conntrack_max=65536 net.ipv4.netfilter.ip_conntrack_tcp_timeout_established=180 net.core.somaxconn = 16384 net.core.netdev_max_backlog = 16384
[root@localhost ~]# sysctl -p #配置生效 net.ipv4.ip_forward = 0 net.ipv4.conf.default.rp_filter = 1 net.ipv4.conf.default.accept_source_route = 0 kernel.sysrq = 0 kernel.core_uses_pid = 1 net.ipv4.tcp_syncookies = 1 kernel.msgmnb = 65536 kernel.msgmax = 65536 kernel.shmmax = 68719476736 kernel.shmall = 4294967296 net.ipv4.tcp_syn_retries = 1 net.ipv4.tcp_synack_retries = 1 net.ipv4.tcp_keepalive_time = 600 net.ipv4.tcp_keepalive_probes = 3 net.ipv4.tcp_keepalive_intvl = 15 net.ipv4.tcp_retries2 = 5 net.ipv4.tcp_fin_timeout = 2 net.ipv4.tcp_max_tw_buckets = 36000 net.ipv4.tcp_tw_recycle = 1 net.ipv4.tcp_tw_reuse = 1 net.ipv4.tcp_max_orphans = 32768 net.ipv4.tcp_syncookies = 1 net.ipv4.tcp_max_syn_backlog = 16384 net.ipv4.tcp_wmem = 8192 131072 16777216 net.ipv4.tcp_rmem = 32768 131072 16777216 net.ipv4.tcp_mem = 786432 1048576 1572864 net.ipv4.ip_local_port_range = 1024 65000 error: "net.ipv4.ip_conntrack_max" is an unknown key error: "net.ipv4.netfilter.ip_conntrack_max" is an unknown key error: "net.ipv4.netfilter.ip_conntrack_tcp_timeout_established" is an unknown key net.core.somaxconn = 16384 net.core.netdev_max_backlog = 16384
6： 超時設置（timeout）
為了系統的安全，設置無操作超時自動退出登錄設置
臨時生效：
[root@centos6 ~]# export TMOUT=5 [root@centos6 ~]# timed out waiting for input: auto-logout
永久配置生效：
[root@centos6 ~]# echo "export TMOUT=300" >>/etc/profile 實際生產環境 5 分鐘 [root@centos6 ~]# source / etc/profile
7： 加大文件描述符
文件描述符是由無符號整數表示的句柄（一般使用範圍0~65535），進程使用它來標識打開的文件。文件描述符與包括相關信息（如文件的打開模式、文件的位置類型、文件的初始類型等）的對象想關聯，這些信息稱為文件的上下文。
對於內核而言，所有打開的文件都是通過文件描述符引用的。當打開一個現有文件或者創建一個新文件時，內核向進程返回一個文件描述符。
按照慣例，UNIX系統shell使用0-》標準輸入，1-》標準輸出，2-》標準錯誤
查看系統默認的文件描述符大小： [root@centos6 ~]# ulimit -n 1024 [root@centos6 ~]# echo "* - nofile 65535">>/etc/security/limits.conf 退出重新登錄，才會生效 [root@centos6 ~]# ulimit -n 65535
8： 隱藏系統版本消息
[cairui@localhost ~]$ cat /etc/issue CentOS release 6.8 (Final) Kernel \r on an \m [cairui@localhost ~]$ cat /etc/issue.net CentOS release 6.8 (Final) Kernel \r on an \m
只需要清空上述的文件內容，就可以隱藏信息。
9： 給grub引導菜單加密碼保護（因為grub能進入看到root密碼）
[root@localhost ~]# /sbin/grub-md5-crypt Password: Retype password: $1$kpiKh/$..jTvOdnHGnMsqqs5OWlM/ [root@localhost ~]# vi /etc/grub.conf [root@localhost ~]# cat /etc/grub.conf # grub.conf generated by anaconda # # Note that you do not have to rerun grub after making changes to this file # NOTICE: You have a /boot partition. This means that # all kernel and initrd paths are relative to /boot/, eg. # root (hd0,0) # kernel /vmlinuz-version ro root=/dev/sda3 # initrd /initrd-[generic-]version.img #boot=/dev/sda default=0 timeout=5 splashimage=(hd0,0)/grub/splash.xpm.gz hiddenmenu password --md5 $1$hv58gkgk9G995885/JG0orl4m #後來添加的 title CentOS 6 (2.6.32-642.el6.x86_64) root (hd0,0) kernel /vmlinuz-2.6.32-642.el6.x86_64 ro root=UUID=57e48303-c321-4c12-8ac4-7596c31f55ef rd_NO_LUKS KEYBOARDTYPE=pc KEYTABLE=us rd_NO_MD crashkernel=auto LANG=zh_CN.UTF-8 rd_NO_LVM rd_NO_DM rhgb quiet initrd /initramfs-2.6.32-642.el6.x86_64.img
10： 調整字符集
[root@centos6 ssh]# echo $LANG en_US.UTF-8 [root@centos6 ssh]# cat /etc/sysconfig/i18n LANG="en_US.UTF-8" SYSFONT="latarcyrheb-sun16" [root@centos6 ssh]# cp /etc/sysconfig/i18n /etc/sysconfig/i18n.2016.12.21 [root@centos6 ssh]# sed -i ‘s#LANG="en_US.UTF-8"#LANG="zh_CN.UTF-8"#g‘ /etc/sysconfig/i18n [root@centos6 ssh]# source /etc/sysconfig/i18n [root@centos6 ssh]# echo $LANG zh_CN.UTF-8
Liunx基礎優化配置