Ifconfig Command Not Found In CentOS 7

CentOS 7 minimal systems, use the commands “ip addr” and “ip link” to find the details of a network interface card. To know the statistics use “ip -s link”.

To view the details of the network interface cards, enter the following commands:

# ip addr

To view the statistics of your network interfaces, enter the command:


# ip link

OR


# ip -s link

How do I enable and use “ifconfig” Command in CentOS 7 minimal servers?


# yum provides ifconfig


# yum install net-tools

Check services on CentOS 7

Check services that are enabled on CentOS 7

# systemctl list-unit-files

Or for a specific service

# systemctl status mysqld

Disabling a service on boot in CentOS 7
To disable, it’s simply a matter of running systemctl disable on the desired service.


# systemctl disable mysqld

Check which services failed to start on boot on CentOS 7
As a bonus, systemctl allows you to list all services that failed to start on boot, even though they were configured to start on boot.


# systemctl --failed

How To Install MySQL – MariaDB on CentOS 7

Install MySQL / MariaDB
Installing MariaDB is as simple as running just one command:


# yum -y install mariadb-server mariadb

And then start MySQL, now MariaDB:


# systemctl start mariadb

Be sure that MySQL/MariaDB starts at boot:


# systemctl enable mariadb

To check the status of MySQL/MariaDB:


# systemctl status mariadb

To top MySQL/MariaDB:


# systemctl stop mariadb

Check the installation with the command client:


# mysql

Reset CentOS Root Password

To reset the root password for CentOS 6:

Boot Computer and Interrupt while booting at GRUB stage hitting ‘arrow‘ keys or “space bar“.
Type ‘a‘ to modify kernel argument. Anytime you can cancel typing ‘ESC‘ key.
Append 1 at the end of “rhgb quiet” and press “Enter” key to boot into single user mode.
Type command “runlevel” to know the the runlevel where you are standing. Here “1 S” state that your are in a single user mode.
Type ‘passwd‘ command without username and press ‘Enter‘ key in command prompt. It’ll ask to supply new root password and re-type the same password for confirmation.

Reboot

# shutdown -r now

CentOS 7

At the boot menu, press e to edit the existing kernel (Core)

Next, scroll down to the list until you see the line underlined below ( ro ) . What we need to do is change that ro to rw and start into a bash shell. It should look like this rw init=/sysroot/bin/sh.

Change the ro line to rw and add init=/sysroot/bin/sh

After changing that, press Control + X or Ctrl + X on your keyboard to start into single user mode using the bash shell specified above. In this mode, we’re going to change the root password.

In the single user mode, run the command as shown below


# chroot /sysroot

Finally, run the commands below to change the root password.


# passwd root

You’ll be prompted to create and confirm a new password. After creating the password, run the commands below to update SELinux parameters

touch /.autorelabel

Reboot

Install ClamAV on CentOS 7

Install ClamAV and set up scheduled scans.

Install Epel:

# yum install epel-release

Install ClmAV

# yum install clamav-server clamav-data clamav-update clamav-filesystem clamav clamav-scanner-systemd clamav-devel clamav-lib clamav-server-systemd
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
 * base: mirror.lax.hugeserver.com
 * epel: dl.fedoraproject.org
 * extras: dallas.tx.mirror.xygenhosting.com
 * updates: linux.mirrors.es.net
Package clamav-data-0.98.7-1.el7.noarch already installed and latest version
Package clamav-filesystem-0.98.7-1.el7.noarch already installed and latest version
Package clamav-lib-0.98.7-1.el7.x86_64 already installed and latest version
Resolving Dependencies
--> Running transaction check
---> Package clamav.x86_64 0:0.98.7-1.el7 will be installed
---> Package clamav-devel.x86_64 0:0.98.7-1.el7 will be installed
---> Package clamav-scanner-systemd.noarch 0:0.98.7-1.el7 will be installed
--> Processing Dependency: clamav-scanner = 0.98.7-1.el7 for package: clamav-scanner-systemd-0.98.7-1.el7.noarch
---> Package clamav-server.x86_64 0:0.98.7-1.el7 will be installed
--> Processing Dependency: nc for package: clamav-server-0.98.7-1.el7.x86_64
---> Package clamav-server-systemd.noarch 0:0.98.7-1.el7 will be installed
---> Package clamav-update.x86_64 0:0.98.7-1.el7 will be installed
--> Running transaction check
---> Package clamav-scanner.noarch 0:0.98.7-1.el7 will be installed
---> Package nmap-ncat.x86_64 2:6.40-7.el7 will be installed
--> Finished Dependency Resolution

Dependencies Resolved

===================================================================================================================================================================================================
 Package                                                   Arch                                      Version                                         Repository                               Size
===================================================================================================================================================================================================
Installing:
 clamav                                                    x86_64                                    0.98.7-1.el7                                    epel                                    806 k
 clamav-devel                                              x86_64                                    0.98.7-1.el7                                    epel                                     37 k
 clamav-scanner-systemd                                    noarch                                    0.98.7-1.el7                                    epel                                     19 k
 clamav-server                                             x86_64                                    0.98.7-1.el7                                    epel                                     93 k
 clamav-server-systemd                                     noarch                                    0.98.7-1.el7                                    epel                                     19 k
 clamav-update                                             x86_64                                    0.98.7-1.el7                                    epel                                     89 k
Installing for dependencies:
 clamav-scanner                                            noarch                                    0.98.7-1.el7                                    epel                                     26 k
 nmap-ncat                                                 x86_64                                    2:6.40-7.el7                                    base                                    201 k

Transaction Summary
===================================================================================================================================================================================================
Install  6 Packages (+2 Dependent packages)

Total download size: 1.3 M
Installed size: 3.0 M
Is this ok [y/d/N]: y
Downloading packages:
(1/8): clamav-0.98.7-1.el7.x86_64.rpm                                                                                                                                       | 806 kB  00:00:00
(2/8): clamav-devel-0.98.7-1.el7.x86_64.rpm                                                                                                                                 |  37 kB  00:00:00
(3/8): clamav-scanner-0.98.7-1.el7.noarch.rpm                                                                                                                               |  26 kB  00:00:00
(4/8): clamav-scanner-systemd-0.98.7-1.el7.noarch.rpm                                                                                                                       |  19 kB  00:00:00
(5/8): clamav-server-0.98.7-1.el7.x86_64.rpm                                                                                                                                |  93 kB  00:00:00
(6/8): clamav-server-systemd-0.98.7-1.el7.noarch.rpm                                                                                                                        |  19 kB  00:00:00
(7/8): clamav-update-0.98.7-1.el7.x86_64.rpm                                                                                                                                |  89 kB  00:00:00
(8/8): nmap-ncat-6.40-7.el7.x86_64.rpm                                                                                                                                      | 201 kB  00:00:00
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Total                                                                                                                                                              1.3 MB/s | 1.3 MB  00:00:00
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
  Installing : 2:nmap-ncat-6.40-7.el7.x86_64                                                                                                                                                   1/8
  Installing : clamav-server-0.98.7-1.el7.x86_64                                                                                                                                               2/8
  Installing : clamav-server-systemd-0.98.7-1.el7.noarch                                                                                                                                       3/8
  Installing : clamav-scanner-0.98.7-1.el7.noarch                                                                                                                                              4/8
  Installing : clamav-scanner-systemd-0.98.7-1.el7.noarch                                                                                                                                      5/8
  Installing : clamav-0.98.7-1.el7.x86_64                                                                                                                                                      6/8
  Installing : clamav-update-0.98.7-1.el7.x86_64                                                                                                                                               7/8
  Installing : clamav-devel-0.98.7-1.el7.x86_64                                                                                                                                                8/8
  Verifying  : clamav-scanner-systemd-0.98.7-1.el7.noarch                                                                                                                                      1/8
  Verifying  : clamav-server-0.98.7-1.el7.x86_64                                                                                                                                               2/8
  Verifying  : clamav-scanner-0.98.7-1.el7.noarch                                                                                                                                              3/8
  Verifying  : clamav-devel-0.98.7-1.el7.x86_64                                                                                                                                                4/8
  Verifying  : clamav-server-systemd-0.98.7-1.el7.noarch                                                                                                                                       5/8
  Verifying  : clamav-update-0.98.7-1.el7.x86_64                                                                                                                                               6/8
  Verifying  : 2:nmap-ncat-6.40-7.el7.x86_64                                                                                                                                                   7/8
  Verifying  : clamav-0.98.7-1.el7.x86_64                                                                                                                                                      8/8

Installed:
  clamav.x86_64 0:0.98.7-1.el7                        clamav-devel.x86_64 0:0.98.7-1.el7          clamav-scanner-systemd.noarch 0:0.98.7-1.el7         clamav-server.x86_64 0:0.98.7-1.el7
  clamav-server-systemd.noarch 0:0.98.7-1.el7         clamav-update.x86_64 0:0.98.7-1.el7

Dependency Installed:
  clamav-scanner.noarch 0:0.98.7-1.el7                                                                nmap-ncat.x86_64 2:6.40-7.el7

Complete!

Copy a the clamd.conf template, in case you don’t have a configuration file yet:

# cp /usr/share/clamav/template/clamd.conf /etc/clamd.d/clamd.conf

Change the file and Comment out “Example”

# nano /etc/clamd.d/clamd.conf

Change this…

# Comment or remove the line below.
Example

To this…

# Comment or remove the line below.
#Example

Configure SELinux for ClamAV.

Check if selinux in on:

# getenforce
Enforcing
[root@database ~]# sestatus
SELinux status:                 enabled
SELinuxfs mount:                /sys/fs/selinux
SELinux root directory:         /etc/selinux
Loaded policy name:             targeted
Current mode:                   enforcing
Mode from config file:          enforcing
Policy MLS status:              enabled
Policy deny_unknown status:     allowed
Max kernel policy version:      28

Write this command to get it working with SELinux if this is active:


# setsebool -P antivirus_can_scan_system 1

Enabling and Disabling SELinux


nano /etc/sysconfig/selinux

To enable…set this to enforcing


# SELINUX=enforcing

To disable, set to permissive

# SELINUX=permissive

Reboot after changes

Or, to make temp changes:

# setenforce permissive

Enable Freshclam

# cp /etc/freshclam.conf /etc/freshclam.conf.bak

Edit the config file to comment out example

# nano /etc/freshclam.conf
# Comment or remove the line below.
#Example

Creat a file

# nano /usr/lib/systemd/system/clam-freshclam.service

Add

# Run the freshclam as daemon
[Unit]
Description = freshclam scanner
After = network.target
 
[Service]
Type = forking
ExecStart = /usr/bin/freshclam -d -c 4
Restart = on-failure
PrivateTmp = true
 
[Install]
WantedBy=multi-user.target

Let’s enable and start the service

# systemctl enable clam-freshclam.service
# systemctl start clam-freshclam.service

rename the /usr/lib/systemd/system/clamd@.service file

# mv /usr/lib/systemd/system/clamd@.service /usr/lib/systemd/system/clamd.service

change the clamd@scan service as well. Change this line in /usr/lib/systemd/system/clamd@scan.service and remove the @ sign

# nano /usr/lib/systemd/system/clamd@scan.service

From…

# .include /lib/systemd/system/clamd@.service

to…

# .include /lib/systemd/system/clamd.service

change the clamd service file /usr/lib/systemd/system/clamd.service:

[Unit]
Description = clamd scanner daemon
After = syslog.target nss-lookup.target network.target
 
[Service]
Type = simple
ExecStart = /usr/sbin/clamd -c /etc/clamd.d/clamd.conf --nofork=yes
Restart = on-failure
PrivateTmp = true
 
[Install]
WantedBy=multi-user.target

Start all services

#cd /usr/lib/systemd/system
# systemctl enable clamd.service
# systemctl enable clamd@scan.service
# systemctl start clamd.service
# systemctl start clamd@scan.service.

Run a scan

# clamscan -i -r --log=/var/log/clamscan-date.txt /var/www/vhosts/*

----------- SCAN SUMMARY -----------
Known viruses: 4159219
Engine version: 0.98.7
Scanned directories: 3
Scanned files: 116
Infected files: 0
Data scanned: 13.64 MB
Data read: 39.54 MB (ratio 0.34:1)
Time: 10.738 sec (0 m 10 s)

Set up a cron to run a scan (example is for a plesk server for the virtual hosts

# nano /etc/cron.daily/clamscan
#!/bin/bash
# setup the scan location and scan log
CLAM_SCAN_DIR="/var/www/vhosts"
CLAM_LOG_FILE="/var/log/clamav/dailyscan.log"
# update the virus database
/usr/bin/freshclam
# run the scan
/usr/bin/clamscan -i -r $CLAM_SCAN_DIR >> $CLAM_LOG_FILE
MAILTO=user@domain.com

Set the cron file as an executible


# chmod 555 /etc/cron.daily/clamscan

Test your installation and cron job


# /etc/cron.daily/clamscan

Nagios

Nagois error on CentOS 7
make stage…

./stdio.h:456:1: error: ‘gets’ undeclared here (not in a function)
Edit the studio.h file, and replace:
#undef gets
_GL_WARN_ON_USE (gets, "gets is a security hole - use fgets instead");
with
#if defined gets
#undef gets
_GL_WARN_ON_USE (gets, "gets is a security hole - use fgets instead");
#endif

Add port 80 to firewalld CentOS 7

By default the port 80 for http connection is filtered on Redhat 7 as you can only access this port from the actual localhost and not from any other public host. To open a port 80 on RHEL 7 Linux we need to add an iptables rule. For this RHEL7 uses firewall-cmd. First add your port 80 rule with a following command:

# firewall-cmd --permanent --zone=public --add-port=80/tcp --permanent

Once you add the above firewall rule reload firewall service:


# firewall-cmd --reload


# firewall-cmd --permanent --zone=<zone> --add-service=http


# firewall-cmd --permanent --zone=<zone> --add-port=80/tcp

You can check if the port has actually be opened by running:


# firewall-cmd --zone=<zone> --query-port=80/tcp


# firewall-cmd --zone=<zone> --query-service=http

Imagemagick on CentOS and Plesk

root@server ~]# yum install ImageMagick
[root@server ~]# yum install ImageMagick-devel

PHP-imagick Installation:
[root@server ~]# yum install gcc
[root@server ~]# yum install make automake
[root@server ~]# yum install php-pear
[root@server ~]# yum install php-devel
[root@server ~]# pecl install imagick

On some servers

yum install php-pecl-imagick.x86_64

Test:

convert image.jpg -resize 64x64 resize_image.jpg

Stop firewalld on CentOS 7

To disable firewalld, run the following command as root:


# systemctl disable firewalld

To stop firewalld, run the following command as root:


# systemctl stop firewalld

To check the status of firewalld, run the following command as root:


# systemctl status firewalld

To enable firewalld, run the following command as root:


# systemctl enable firewalld

To start firewalld, run the following command as root:


# systemctl start firewalld

Other information:

https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/Security_Guide/sec-Using_Firewalls.html