Category: Ubuntu – ServerOK

install ShadowSocks client in Ubuntu 18.04

August 26, 2019

by ServerOk with No Comment Ubuntu

ShadowSocks client is part of shadowsocks package. This include both client and server. If you are looking to install server, see Install ShadowSocks server on Debian 10

To install ShadowSocks, run

apt install -y shadowsocks

1	apt install -y shadowsocks

ShadowSocks client is called sslocal, get installed in /usr/bin/sslocal.

On Ubuntu, no start up script provided with this package, so you need to create one or manually run sslocal when required.

Create a service file

vi /lib/systemd/system/shadowsocks-local@.service

1	vi /lib/systemd/system/shadowsocks-local@.service

Add following content

[Unit]
Description=Shadowsocks client mode service
Documentation=man:sslocal(1)
After=network-online.target

[Service]
Type=simple
User=nobody
Group=nogroup
ExecStart=/usr/bin/sslocal -q -c /etc/shadowsocks/%i.json
Restart=on-failure
RestartSec=30

[Install]
WantedBy=multi-user.target

[Unit]

Description=Shadowsocks client mode service

Documentation=man:sslocal(1)

After=network-online.target

[Service]

Type=simple

User=nobody

Group=nogroup

ExecStart=/usr/bin/sslocal -q -c /etc/shadowsocks/%i.json

Restart=on-failure

RestartSec=30

[Install]

WantedBy=multi-user.target

Now we need to create a configuration file with your ShadowSocks server IP and password.

mkdir /etc/shadowsocks/
vi /etc/shadowsocks/local.json

1 2	mkdir /etc/shadowsocks/ vi /etc/shadowsocks/local.json

Add following content

{
    "server":"YOUR_SERVER_IP",
    "server_port":8044,
    "local_address": "127.0.0.1",
    "local_port":8044,
    "password":"PASSWORD",
    "timeout":300,
    "method":"aes-256-cfb",
    "fast_open": false,
    "workers": 1,
    "prefer_ipv6": false
}

{

"server":"YOUR_SERVER_IP",

"server_port":8044,

"local_address": "127.0.0.1",

"local_port":8044,

"password":"PASSWORD",

"timeout":300,

"method":"aes-256-cfb",

"fast_open": false,

"workers": 1,

"prefer_ipv6": false

}

“server” = IP of the server where you installled ShadowSocks server.
“server_port” = Port used by ShadowSocks server
“password” = ShadowSocks server password.

local_port can be anything you like.

Enable shadowsocks service

systemctl enable shadowsocks-local@local

1	systemctl enable shadowsocks-local@local

To start

systemctl start shadowsocks-local@local

1	systemctl start shadowsocks-local@local

To see status

systemctl status shadowsocks-local@local

1	systemctl status shadowsocks-local@local

Now you can configure your browser or other sock proxy supported application using 127.0.0.1:8044. Here is how to configure firefox

Setting up MineCraft Server in Ubuntu

August 20, 2019

by ServerOk with No Comment Ubuntu

To setup MineCraft server on Ubuntu, first you need to install Java.

apt install openjdk-8-jre -y

1	apt install openjdk-8-jre -y

Create a user to run minecraft

useradd -m --shell /bin/bash minecraft

1	useradd -m --shell /bin/bash minecraft

You can set a password if you want direct SSH login to this user or login as root, then “su – minecraft”.

passwd minecraft

1	passwd minecraft

Download minecraft server .jar file from

https://www.minecraft.net/en-us/download/server/

At the time of writing, i downloaded

wget https://launcher.mojang.com/v1/objects/3dc3d84a581f14691199cf6831b71ed1296a9fdf/server.jar

1	wget https://launcher.mojang.com/v1/objects/3dc3d84a581f14691199cf6831b71ed1296a9fdf/server.jar

Don’t use above link as it can get older, always go to minecraft site and get new link, so you get latest minecraft server jar file.

You can start minecraft server with command

java -Xmx1024M -Xms1024M -jar server.jar nogui

1	java -Xmx1024M -Xms1024M -jar server.jar nogui

First time when you run, it exit with some error related to EULA.

You need to edit file

vi eula.txt

1	vi eula.txt

Set

eula=true

eula=true

Now minecraft will run. You can create a run.sh file with following command for starting minecrat easily.

vi ~/start.sh

1	vi ~/start.sh

Paste following content

#!/bin/bash

java -Xmx1024M -Xms1024M -jar server.jar nogui

#!/bin/bash

java -Xmx1024M -Xms1024M -jar server.jar nogui

To make the file executable, chmod it 755

chmod 755 ~/start.sh

1	chmod 755 ~/start.sh

When you start minecraft from terminal/ssh, it get closed when you disconnect. To keep minecraft server running after you disconnect, use tmux or screen.

networking

August 18, 2019

by ServerOk with No Comment Ubuntu

On Ubuntu 19.04, networking service is provided by package ifupdown

apt install -y ifupdown

1	apt install -y ifupdown

By default this package is not installed. So if you add network interface configuration in /etc/network/interfaces, it won’t work.

Ubuntu 18.04 + use netplan instead of ifupdown/networking service to configure network interfaces.

Configure OVH Bridge Network from command line

Ubuntu Configure systemd-resolved

August 18, 2019

by ServerOk with No Comment Ubuntu

Latest Ubuntu/Debian use systemd-resolved for DNS resolution. On a fresh Ubuntu 19.04 install DNS failed to resolve.

root@ubuntu19:/# ping serverok.in
ping: serverok.in: Temporary failure in name resolution
root@ubuntu19:/#

root@ubuntu19:/# ping serverok.in

ping: serverok.in: Temporary failure in name resolution

root@ubuntu19:/#

To fix this, create file

mkdir /etc/systemd/resolved.conf.d/
vi /etc/systemd/resolved.conf.d/dns_servers.conf

1 2	mkdir /etc/systemd/resolved.conf.d/ vi /etc/systemd/resolved.conf.d/dns_servers.conf

Add content

[Resolve]
DNS=8.8.8.8 1.1.1.1

1 2	[Resolve] DNS=8.8.8.8 1.1.1.1

Restart systemd-resolved

systemctl restart systemd-resolved

1	systemctl restart systemd-resolved

You can find systemd-resolvd status with command

resolvectl status
systemd-resolve --status

1 2	resolvectl status systemd-resolve --status

To resolve a domain, use

resolvectl query serverok.in

1	resolvectl query serverok.in

Ubuntu remove SSH welcome message

August 17, 2019

by ServerOk with No Comment Ubuntu

When you login to an Ubuntu server using SSH, you get welcome message like

On most Linux systems, this is generated by /etc/motd. On Ubuntu, MOTD (message of the day) generated dynamically with some scripts. I don’t want to see all the marketing message from Ubuntu everyday.

To disable MOTD on Ubuntu, just delete the scripts from /etc/update-motd.d/

rm -f /etc/update-motd.d/*

1	rm -f /etc/update-motd.d/*

If you want a differnt motd, you can put a shell script in this folder.

Method 2

Another way to disable motd is by disabling pam_motd.so module.

Edit files

/etc/pam.d/login
/etc/pam.d/sshd

1 2	/etc/pam.d/login /etc/pam.d/sshd

Comment out the lines related to pam_motd.so

session    optional     pam_motd.so  motd=/run/motd.dynamic
session    optional     pam_motd.so noupdate

1 2	session optional pam_motd.so motd=/run/motd.dynamic session optional pam_motd.so noupdate

Install Linux Kernel 5.0 on Ubuntu 18.04 LTS

August 16, 2019

by ServerOk with No Comment Ubuntu

Ubuntu 18.04 was released with Linux kernel 4.15

root@DUS-147022:~# hostnamectl
   Static hostname: DUS-147022.op-net.com
         Icon name: computer-desktop
           Chassis: desktop
        Machine ID: 1fcb383ac03e4299a3b994dca4c51a10
           Boot ID: 66d616e9b11145c38387d71f9c48a4bd
  Operating System: Ubuntu 18.04.3 LTS
            Kernel: Linux 4.15.0-58-generic
      Architecture: x86-64
root@DUS-147022:~#

root@DUS-147022:~# hostnamectl

Static hostname: DUS-147022.op-net.com

Icon name: computer-desktop

Chassis: desktop

Machine ID: 1fcb383ac03e4299a3b994dca4c51a10

Boot ID: 66d616e9b11145c38387d71f9c48a4bd

Operating System: Ubuntu 18.04.3 LTS

Kernel: Linux 4.15.0-58-generic

Architecture: x86-64

root@DUS-147022:~#

On 8 Aug 2019, Cannonical released Ubuntu 18.04.3 LTS with Linux Kernel 5.0.

If you are using older Ubuntu 18.04 point release, you won’t get newer kernel when you do software upgrade.

To get newer Linux kernal installed, you need to install Hardware enablement (HWE) stack, this provide newer kernel that provide support for latest hardware.

To install Hardware enablement (HWE) stack, run

apt install linux-generic-hwe-18.04

1	apt install linux-generic-hwe-18.04

if this is Desktop computer, you may need to run

apt install linux-generic-hwe-18.04 xserver-xorg-hwe-18.04

1	apt install linux-generic-hwe-18.04 xserver-xorg-hwe-18.04

after installing, reboot

reboot

reboot

after reboot, you will see latest Linux Kernel.

boby@sok-01:~$ hostnamectl
   Static hostname: sok-01
         Icon name: computer-desktop
           Chassis: desktop
        Machine ID: 70486772aac1410c9a8031851ab60a0d
           Boot ID: 6c946c08f95d4c6b883e6790ab83e728
  Operating System: Ubuntu 18.04.3 LTS
            Kernel: Linux 5.0.0-25-generic
      Architecture: x86-64
boby@sok-01:~$

boby@sok-01:~$ hostnamectl

Static hostname: sok-01

Icon name: computer-desktop

Chassis: desktop

Machine ID: 70486772aac1410c9a8031851ab60a0d

Boot ID: 6c946c08f95d4c6b883e6790ab83e728

Operating System: Ubuntu 18.04.3 LTS

Kernel: Linux 5.0.0-25-generic

Architecture: x86-64

boby@sok-01:~$

Ubuntu allow a normal user to edit WiFi Connection

August 7, 2019

by ServerOk with No Comment Ubuntu

When a normal user edit Wi-Fi connection on Wi-Fi Settings, they will be asked to enter administrator user pasword.

To allow a normal user to modify network connection, you can edit the connection configuration file in folder

/etc/NetworkManager/system-connections

1	/etc/NetworkManager/system-connections

This file look like

root@sok-01:/etc/NetworkManager/system-connections# cat SOK
[connection]
id=SOK
uuid=982596a7-44c8-4e52-a696-6acf4daeec12
type=wifi
permissions=

[wifi]
mac-address=E8:DE:27:0B:39:55
mac-address-blacklist=
mode=infrastructure
ssid=SOK

[wifi-security]
auth-alg=open
key-mgmt=wpa-psk
psk=Sup3rD0nkey

[ipv4]
dns-search=
method=auto

[ipv6]
addr-gen-mode=stable-privacy
dns-search=
method=auto
root@sok-01:/etc/NetworkManager/system-connections#

root@sok-01:/etc/NetworkManager/system-connections# cat SOK

[connection]

id=SOK

uuid=982596a7-44c8-4e52-a696-6acf4daeec12

type=wifi

permissions=

[wifi]

mac-address=E8:DE:27:0B:39:55

mac-address-blacklist=

mode=infrastructure

ssid=SOK

[wifi-security]

auth-alg=open

key-mgmt=wpa-psk

psk=Sup3rD0nkey

[ipv4]

dns-search=

method=auto

[ipv6]

addr-gen-mode=stable-privacy

dns-search=

method=auto

root@sok-01:/etc/NetworkManager/system-connections#

Find

permissions=

1	permissions=

Replace with

permissions=user:USER_NAME_HEARE:;

1	permissions=user:USER_NAME_HEARE:;

USER_NAME_HEARE = replace this with actual username, that need to edit the network configuration.

MariaDB Repository Setup Script

July 27, 2019

by ServerOk with No Comment Ubuntu

This script configure MariaDB repository on your server. You can find more details on offical page

https://mariadb.com/kb/en/library/mariadb-package-repository-setup-and-usage/

To setup mariadb repo, run

curl -sS https://downloads.mariadb.com/MariaDB/mariadb_repo_setup | sudo bash

1	curl -sS https://downloads.mariadb.com/MariaDB/mariadb_repo_setup \| sudo bash

I was expecting it ask me what version of MariaDB i like to setup. But it just setup MariaDB 10.4. I wanted to upgrade MariaDB to version 10.2, anyway i did upgrade to 10.4 and everything worked fine.

If you need a speicfic version, you can run like

curl -sS https://downloads.mariadb.com/MariaDB/mariadb_repo_setup | sudo bash -s -- --mariadb-server-version="mariadb-10.3"

1	curl -sS https://downloads.mariadb.com/MariaDB/mariadb_repo_setup \| sudo bash -s -- --mariadb-server-version="mariadb-10.3"

Availabe versions are

mariadb-5.5
mariadb-10.0
mariadb-10.1
mariadb-10.2
mariadb-10.3
mariadb-10.4

mariadb-5.5

mariadb-10.0

mariadb-10.1

mariadb-10.2

mariadb-10.3

mariadb-10.4

When i run the script on Debian 9 server, i get following error

root@server:~# curl -sS https://downloads.mariadb.com/MariaDB/mariadb_repo_setup | sudo bash
[info] Repository file successfully written to /etc/apt/sources.list.d/mariadb.list
[info] Adding trusted package signing keys...
Executing: /tmp/apt-key-gpghome.TKjSzTY6ww/gpg.1.sh --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 0x8167EE24 0xE3C94F49 0xcbcb082a1bb943db 0xF1656F24C74CD1D8 0x135659e928c12247
gpg: failed to start the dirmngr '/usr/bin/dirmngr': No such file or directory
gpg: connecting dirmngr at '/run/user/0/gnupg/d.3y8gtbm7kaj8h4royj6yoyug/S.dirmngr' failed: No such file or directory
gpg: keyserver receive failed: No dirmngr
[error] Failed to add trusted package signing keys.
root@server:~#

root@server:~# curl -sS https://downloads.mariadb.com/MariaDB/mariadb_repo_setup | sudo bash

[info] Repository file successfully written to /etc/apt/sources.list.d/mariadb.list

[info] Adding trusted package signing keys...

Executing: /tmp/apt-key-gpghome.TKjSzTY6ww/gpg.1.sh --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 0x8167EE24 0xE3C94F49 0xcbcb082a1bb943db 0xF1656F24C74CD1D8 0x135659e928c12247

gpg: failed to start the dirmngr '/usr/bin/dirmngr': No such file or directory

gpg: connecting dirmngr at '/run/user/0/gnupg/d.3y8gtbm7kaj8h4royj6yoyug/S.dirmngr' failed: No such file or directory

gpg: keyserver receive failed: No dirmngr

[error] Failed to add trusted package signing keys.

root@server:~#

This is fixed by running

apt -y install dirmngr

1	apt -y install dirmngr

Enable Remote Desktop in Ubuntu 18.04

July 27, 2019

by ServerOk with No Comment Ubuntu

To enable remote desktop on Ubuntu 18.04 (works with newer Ubuntu versions), go to settings.

Click on Sharing

Click on ON/OFF button on title bar to enable Desktop Sharing. Once enabled, click on “Screen Sharing” to See Desktop sharing option, you need to enable it for network connection.

Ubuntu use vino package to allow remote desktop over VNC.

See Ubuntu, VNC, remote desktop

Install x11vnc on Ubuntu

July 17, 2019

by ServerOk with No Comment Ubuntu

To install x11vnc on Debian/Ubuntu, run

apt install -y x11vnc

1	apt install -y x11vnc

To start vnc server, run

x11vnc -display :0

1	x11vnc -display :0

By default, there will be no password. To set password, run

x11vnc -storepasswd

1	x11vnc -storepasswd

To start x11vnc server with password, run

x11vnc -rfbauth ~/.vnc/passwd

1	x11vnc -rfbauth ~/.vnc/passwd