Kami menggunkaan Rocky Linux 9.4 (Blue Onyx) dengan kondisi service postfix sudah diinstall.

• Buat file sasl_passwd di direktori /etc/postfix

# vim /etc/postfix/sals_passwd

• isikan konfigurasi authentication dari server SMTP Relay

relay.domain.com rizkiana.my.id:passwordsmtprelay

• Postmap file sasl_passwd

# postmap sasl_passwd

• Buka file /etc/postfix/main.cf untuk konfigurasi relay (sesuaikan dengan konfigurasi relay yang diberikan oleh provider)

# vim /etc/postfix/main.cf


relayhost = [relay.domain.com]:587
smtp_sasl_auth_enable = yes
smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd
smtp_sasl_security_options = noanonymous
smtp_use_tls = yes
smtp_tls_security_level = may
mynetworks = 127.0.0.0/8 IP-ADDRESS-SMTPLAIN/32

• Restart service postfix

# systemctl restart postfix

• Lakukan pengtetesan email dan pantau log /var/log/maillog, apabila anda mendapatkan error seperti berikut :

Jun  5 18:54:19 rocky postfix/smtp[7541]: AB437F201CB: to=<yogi@rizkiana.my.id>, relay=relay.domain.com[IP ADDRESS RELAY]:587, delay=9.5, delays=8.1/0/1.4/0, dsn=4.7.0, status=deferred (SASL auth
entication failed; cannot authenticate to server relay.domain.com[IP ADDRESS RELAY]: no mechanism available

• Install package pendukung

# yum install cyrus-sasl-plain

• Lakukan pengtetesan email kembali dan pantau log /var/log/maillog, apabila anda mendapatkan error seperti berikut :

Jun  5 19:23:11 rocky postfix/smtp[7541]: AB437F201CB: to=<yogi@rizkiana.my.id>, relay=relay.domain.com[IP ADDRESS RELAY]:587, delay=859, delays=841/0.1/1.1/17, dsn=2.0.0, status=sent (250 OK id=1sEpR6-004NfN-6t)

Baca juga : Mengatasi Tracking Center Log Proxmox Mail Gateway Kosong (Tidak Muncul)

Semoga bermanfaat & enjoy. Wassalamualaikum

The post Setup Relay Authentication di Postfix appeared first on rizkiana.my.id.

Saat ini, server saya menjalankan CentOS 6.7. Berikut cara update CentOS dari 6.7 ke 6.10 (Final).

• Cek versi CentOS yang digunakan saat ini

# cat /etc/redhat-release 
CentOS release 6.7 (Final)

Note: Sebelum melakukan update, pastikan Anda telah membuat cadangan semua data Anda ya. DWYOR!!!

• Gunakan perintah yum update untuk melakukan update sistem yang sedang berjalan

# yum clean all
# yum update

Note: Proses update akan membutuhkan waktu tergantung dari kecepatan internet yang diberikan pada server, pastikan internet pada server anda sudah siap ya untuk mendownload paket-paket yang diperlukan selama proses update berlangsung.

• Setelah berhasil menyelesaikan perintah di atas, reboot sistem Anda

# reboot

• Terakhir, verifikasi bahwa sistem Anda telah berhasil ditingkatkan atau update. Untuk mengkonfirmasinya periksa versi CentOS saat ini

# cat /etc/redhat-release

CentOS release 6.10 (Final)

Proses update CentOS dari 6.7 ke 6.10 sudah selesai dilakukan , saat ini kita sudah menggunakan CentOS versi latest (paling terbaru) yaitu, CentOS 6.10 (Final) dari yang sebelumnya yaitu,CentOS 6.7 (Final)

Refrensi | Baca juga : Mengatasi crontab zimbra user yang hilang

Semoga bermanfaat & enjoy. Wassalamualaikum

The post Cara Update CentOS dari 6.7 ke 6.10 (Final) appeared first on rizkiana.my.id.

Pesan error yang didapatkan ketika melakukan instalasi packet ialah sebagai berikut :

[root@serverX ~]# yum install libevent
Loaded plugins: fastestmirror
Setting up Install Process
Loading mirror speeds from cached hostfile
Error: Cannot retrieve metalink for repository: epel. Please verify its path and try again

Setelah mencoba beberapa cara akhirnya permasalahan tersebut dapat diatasi atau diselesaikan, berikut ialah cara untuk mengtasi Error: Cannot retrieve metalink for repository: epel. Please verify its path and try again ketika melakukan instalasi sebuah packet di CentOs atau RedHat :

• Buka file /etc/yum.repos.d/epel.repo menggunkan text editor favorit anda

[epel]
name=Extra Packages for Enterprise Linux 6 - $basearch
baseurl=http://download.fedoraproject.org/pub/epel/6/$basearch
mirrorlist=https://mirrors.fedoraproject.org/metalink?repo=epel-6&arch=$basearch
failovermethod=priority
enabled=1
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6

[epel-debuginfo]
name=Extra Packages for Enterprise Linux 6 - $basearch - Debug
baseurl=http://download.fedoraproject.org/pub/epel/6/$basearch/debug
mirrorlist=https://mirrors.fedoraproject.org/metalink?repo=epel-debug-6&arch=$basearch
failovermethod=priority
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6
gpgcheck=1

[epel-source]
name=Extra Packages for Enterprise Linux 6 - $basearch - Source
baseurl=http://download.fedoraproject.org/pub/epel/6/SRPMS
mirrorlist=https://mirrors.fedoraproject.org/metalink?repo=epel-source-6&arch=$basearch
failovermethod=priority
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6
gpgcheck=1

• Berikan tanda # pada baris mirrorlist seperti berikut :

[epel]
name=Extra Packages for Enterprise Linux 6 - $basearch
baseurl=http://download.fedoraproject.org/pub/epel/6/$basearch
#mirrorlist=https://mirrors.fedoraproject.org/metalink?repo=epel-6&arch=$basearch
failovermethod=priority
enabled=1
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6

[epel-debuginfo]
name=Extra Packages for Enterprise Linux 6 - $basearch - Debug
baseurl=http://download.fedoraproject.org/pub/epel/6/$basearch/debug
#mirrorlist=https://mirrors.fedoraproject.org/metalink?repo=epel-debug-6&arch=$basearch
failovermethod=priority
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6
gpgcheck=1

[epel-source]
name=Extra Packages for Enterprise Linux 6 - $basearch - Source
baseurl=http://download.fedoraproject.org/pub/epel/6/SRPMS
#mirrorlist=https://mirrors.fedoraproject.org/metalink?repo=epel-source-6&arch=$basearch
failovermethod=priority
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6
gpgcheck=1

• Simpan konfigurasi tersebut dengan cara klik Esc + :wq pada keyboard anda
• Kemudian buka file /etc/yum.repos.d/epel-testing.repo menggunkan text editor favorit anda

[epel-testing]
name=Extra Packages for Enterprise Linux 6 - Testing - $basearch
baseurl=http://download.fedoraproject.org/pub/epel/testing/6/$basearch
mirrorlist=https://mirrors.fedoraproject.org/metalink?repo=testing-epel6&arch=$basearch
failovermethod=priority
enabled=0
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6

[epel-testing-debuginfo]
name=Extra Packages for Enterprise Linux 6 - Testing - $basearch - Debug
baseurl=http://download.fedoraproject.org/pub/epel/testing/6/$basearch/debug
mirrorlist=https://mirrors.fedoraproject.org/metalink?repo=testing-debug-epel6&arch=$basearch
failovermethod=priority
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6
gpgcheck=1

[epel-testing-source]
name=Extra Packages for Enterprise Linux 6 - Testing - $basearch - Source
baseurl=http://download.fedoraproject.org/pub/epel/testing/6/SRPMS
mirrorlist=https://mirrors.fedoraproject.org/metalink?repo=testing-source-epel6&arch=$basearch
failovermethod=priority
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6
gpgcheck=1

• Lakukan langlah yang sama seperti file sebelumnya, yaitu file /etc/yum.repos.d/epel yaitu berikan tanda # pada baris mirrorlist seperti berikut :

[epel-testing]
name=Extra Packages for Enterprise Linux 6 - Testing - $basearch
baseurl=http://download.fedoraproject.org/pub/epel/testing/6/$basearch
#mirrorlist=https://mirrors.fedoraproject.org/metalink?repo=testing-epel6&arch=$basearch
failovermethod=priority
enabled=0
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6

[epel-testing-debuginfo]
name=Extra Packages for Enterprise Linux 6 - Testing - $basearch - Debug
baseurl=http://download.fedoraproject.org/pub/epel/testing/6/$basearch/debug
#mirrorlist=https://mirrors.fedoraproject.org/metalink?repo=testing-debug-epel6&arch=$basearch
failovermethod=priority
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6
gpgcheck=1

[epel-testing-source]
name=Extra Packages for Enterprise Linux 6 - Testing - $basearch - Source
baseurl=http://download.fedoraproject.org/pub/epel/testing/6/SRPMS
#mirrorlist=https://mirrors.fedoraproject.org/metalink?repo=testing-source-epel6&arch=$basearch
failovermethod=priority
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6
gpgcheck=1

• Simpan konfigurasi tersebut dengan cara klik Esc + :wq menggunkan text editor favorit anda
• Kemudian lakukan pengetesan instalasi packet yang diinginkan menggunakan yum maka packet akan berhasil di install menggunakan yum dan error tersebut sudah tidak terjadi lagi.

Refrensi | Baca juga: Mengatasi Original IP tidak muncul di log Zimbra

Semoga bermanfaat & enjoy. Wassalamualaikum

The post Error: Cannot retrieve metalink for repository: epel. Please verify its path and try again appeared first on rizkiana.my.id.

Untuk mengatasinya, kita bisa menggunakan software yang bernama ncdu. ncdu, singkatan dari NCurses Disk Usage, adalah versi berbasis gratis dari perintah ‘du’ yang terkenal. Ini memberikan cara cepat untuk melihat direktori apa yang menggunakan ruang disk. Meskipun ada banyak alat dan cara yang tersedia untuk menganalisis penggunaan disk di Linux, pengembang utilitas ini tidak puas dengan semuanya.

Instalasi NCDU

Untuk melakukan instalasi ncdu di CentOS bisa mengikuti cara berikut :

• Instalasi di Arch Linux, Antergos, Manjaro Linux

$ sudo pacman -S ncdu

• Instalasi di RHEL, CentOS, Scientific Linux

$ sudo yum install ncdu

• Instalasi di Fedora

$ sudo dnf install ncdu

• Instalasi di SUSE, openSUSE

$ sudo zypper in ncdu

• Instalasi di Debian, Ubuntu, Linux Mint

$ sudo apt-get install ncdu

Cara Menggunakan NCDU

• Jalankan ncdu menggunakan command line atau terminal masing-masing OS anda

$ ncdu

Note: Diatas ialah proses scanning disk usage menggunakan ncdu

• Berikut ialah cara untuk mengecek disk usage menggunakan ncdu di Linux

Note : Dapat dilihat penggunaan usage tertinggi berada pada direktori /home kemudian disusul oleh /media

Baca juga: Membuat Alias di Zimbra Menggunakan Bash Script

Semoga bermanfaat & enjoy. Wassalamualaikum

The post Mengecek Disk Usage Menggunakan NCDU di Linux appeared first on rizkiana.my.id.

• open file /etc/ssh/sshd_config using vim / nano

# vim /etc/ssh/sshd_config

• Add following this line in the bottom

# Disable Root Login
PermitRootLogin no
UseDNS no

• Restart service ssh

# systemctl restart sshd

Note : Before you disable root login, you MUST create a new user and give sudoers access, because if you don’t create a new user then your server will not be accessible

Read this : Menambahkan User ke Sudoers di CentOS/Red Hat

May be usefull & enjoy, wassalamualaikum

The post Disable Root Login in CentOS/Red Hat appeared first on rizkiana.my.id.

• Untuk melakukan konfigurasi ini pastikan terlebih dahulu membuat user rizkiana terlebih dahulu

# adduser rizkiana
# passwd rizkiana
Enter new UNIX password: rizkiana-password
Retype new UNIX password: rizkiana-password

• Buka file /etc/sudoers dengan text editor favorit anda

# vim /etc/sudoers

• Pada baris berikut tambahkan user yang baru kita buat seperti berikut :

## Allow root to run any commands anywhere 
root    ALL=(ALL)       ALL
rizkiana    ALL=(ALL)       ALL

• Testing ssh menggunakan user rizkiana dan akses ke sudo su

$ ssh rizkiana@server.lab
rizkiana@server.lab's password: rizkiana-password
[riziana@server ~]$ sudo su
[sudo] password for rizkiana: rizkiana-password
[root@server rizkiana]# 

Konfigurasi sudah selesai dan berhasil juga kita testing.

Baca juga : Disable Root Login in CentOS/Red Hat

Semoga bermanfaat & enjoy, wassalamualaikum

The post Menambahkan User Ke Sudoers di CentOS/Red Hat appeared first on rizkiana.my.id.

• For example we have 2 files in same directory and the timestamp from both files is same.

# ll
total 0
-rw-r--r-- 1 root root 0 Apr 19 13:50 file1
-rw-r--r-- 1 root root 0 Apr 19 13:50 file2

• And we want change the timestamp in file1, if we check now the timestamp from file1 is “Apr 19 13:50” and we want change the timestamp to “Mar 30 11:20”, run this command to change the timestamp

# touch -d '30 Mar 2019 11:20' file1 

• And then check again the timestamp for both files

# ll
total 0
-rw-r--r-- 1 root root 0 Mar 30 11:20 file1
-rw-r--r-- 1 root root 0 Apr 19 13:50 file2

Refrence | Read this : a parsing error has occured when import zimbra calendar

We hope this article is useful & enjoy, wassalamualaikum

The post Change Timestamp in CentOS/Red Hat appeared first on rizkiana.my.id.

Bagaimana cara melakukan instalasinya? Berikut ialah cara-nya :

• Install epel-release

# yum install epel-release

• Install fail2ban

# yum install fail2ban

• Konfigurasi file jail.conf yang berada pada direktori /etc/fail2ban , backup terlebih dahulu file jail.conf tersebut sebelum melakukan konfigurasi

# cp /etc/fail2ban/jail.conf /etc/fail2ban/jail.conf.backup

• Edit file jail.conf

# vim /etc/fail2ban/jail.conf

# Fail2Ban configuration file
#
# Author: Cyril Jaquier
#
# $Revision: 747 $
## The DEFAULT allows a global definition of the options. They can be overridden
# in each jail afterwards.
[DEFAULT]
# "ignoreip" can be an IP address, a CIDR mask or a DNS host. Fail2ban will not
# ban a host which matches an address in this list. Several addresses can be
# defined using space separator.
ignoreip = 127.0.0.1/8 192.168.100.101/32
# "bantime" is the number of seconds that a host is banned.
bantime = 15600
# A host is banned if it has generated "maxretry" during the last "findtime"
# seconds.
findtime = 600

# "maxretry" is the number of failures before a host get banned.
maxretry = 3

# "backend" specifies the backend used to get files modification. Available
# options are "gamin", "polling" and "auto". This option can be overridden in
# each jail too (use "gamin" for a jail and "polling" for another).
#
# gamin: requires Gamin (a file alteration monitor) to be installed. If Gamin
# is not installed, Fail2ban will use polling.
# polling: uses a polling algorithm which does not require external libraries.
# auto: will choose Gamin if available and polling otherwise.
backend = auto

[ssh-iptables]
enabled = true
filter = sshd
action = iptables[name=SSH, port=ssh, protocol=tcp]
logpath = /var/log/secure
maxretry = 3

Note : Dari konfigurasi diatas kita akan set untuk sshd dengan membaca log yang berada pada file /var/log/secure dengan maksimal percobaan 3 kali, apabila melebihi 3 kali maka IP tersebut akan diblok selama 15600 detik

• Restart service untuk mengaktifkan fail2ban

# service fail2ban restart

• cek service fail2ban

# service fail2ban status
Redirecting to /bin/systemctl status fail2ban.service
● fail2ban.service - Fail2Ban Service
   Loaded: loaded (/usr/lib/systemd/system/fail2ban.service; disabled; vendor preset: disabled)
   Active: active (running) since Jum 2019-02-22 09:03:50 WIB; 1 months 20 days ago
     Docs: man:fail2ban(1)
 Main PID: 19042 (fail2ban-server)
   CGroup: /system.slice/fail2ban.service
           └─19042 /usr/bin/python2 -s /usr/bin/fail2ban-server -s /var/run/fail2ban/fail2ban.sock -p /var/run/fail2ban/fail2ban.pid -x -b

Warning: Journal has been rotated since unit was started. Log output is incomplete or unavailable.

• Cek IP yang melakukan bruteforce

# iptables -nL
Chain INPUT (policy ACCEPT)
target     prot opt source               destination         
ACCEPT     tcp  --  192.168.100.0/24      0.0.0.0/0            tcp dpt:443
f2b-SSH    tcp  --  0.0.0.0/0            0.0.0.0/0            tcp dpt:22
ACCEPT     tcp  --  0.0.0.0/0            0.0.0.0/0            state NEW tcp dpt:10050

Chain FORWARD (policy ACCEPT)
target     prot opt source               destination         

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination         

Chain f2b-SSH (1 references)
target     prot opt source               destination         
REJECT     all  --  37.187.248.39        0.0.0.0/0            reject-with icmp-port-unreachable
REJECT     all  --  138.197.162.28       0.0.0.0/0            reject-with icmp-port-unreachable
REJECT     all  --  61.0.242.100         0.0.0.0/0            reject-with icmp-port-unreachable
REJECT     all  --  159.65.81.187        0.0.0.0/0            reject-with icmp-port-unreachable

Refrensi | Baca juga : Can’t connect to TCP port 10024 on ::1 [Cannot assign requested address] Zimbra

Semoga bermanfaat & enjoy, wassalamualaikum

The post Instalasi Fail2ban di CentOS/RedHat appeared first on rizkiana.my.id.

Bagaiamana jika kita ingin melakukan SSH ke server kita tanpa menggunakan password?

Berikut caranya untuk melakukan SSH ke server tanpa menggunakan password.

• Jalankan ssh-keygen untuk membuat public-private key pair.

[student@desktopX ~]$ ssh-keygen
Generating public/private rsa key pair.
Enter file in which to save the key (/home/student/.ssh/id_rsa): Enter
Created directory '/home/student/.ssh'.
Enter passphrase (empty for no passphrase): Enter
Enter same passphrase again: Enter
Your identification has been saved in /home/student/.ssh/id_rsa.
Your public key has been saved in /home/student/.ssh/id_rsa.pub.
The key fingerprint is:
a4:49:cf:fb:ac:ab:c8:ce:45:33:f2:ad:69:7b:d2:5a student@desktopX.example.com
The key's randomart image is:
+--[ RSA 2048]----+
|                |
|                |
|      . .       |
|     . *        |
|     . * S      |
|     + + .      |
|      o.E       |
|    o oo+oo     |
|   .=.**ooo     |
+-----------------+

• Kirim ssh public key ke server tujuan menggunakan perintah ssh-copt-id

[student@desktopX ~]$ ssh-copy-id serverX
The authenticity of host 'serverX (172.25.X.11)' can't be established.
ECDSA key fingerprint is 33:fa:a1:3c:98:30:ff:f6:d4:99:00:4e:7f:84:3e:c3.
Are you sure you want to continue connecting (yes/no)? yes
/usr/bin/ssh-copy-id: INFO: attempting to log in with the new key(s), to filter out
any that are already installed
/usr/bin/ssh-copy-id: INFO: 1 key(s) remain to be installed -- if you are prompted
now it is to install the new keys
student@serverX's password: student
Number of key(s) added: 1
Now try logging into the machine, with:
"ssh 'student@serverX'"
and check to make sure that only the key(s) you wanted were added.

• Lakukan testing SSH ke server tujuan dan seharusnya server tidak akan meminta password lagi ketika kita mengaksesnya.

[student@desktopX ~]$ ssh serverX

Refrensi | Baca juga : Tes Koneksi Port Menggunakan Paping

Semoga bermanfaat & enjoy, wassalamualaikum

The post SSH Tanpa Password di Red Hat / Centos appeared first on rizkiana.my.id.