Trang Nguyen trangnth

Ubuntu: Install Kernel and Set GRUB Default Kernel

Install Kernel

Install the default kernel:

sudo apt install linux-generic

Set GRUB Default Kernel

Find entrance from /boot/grub/grub.cfg
- Get the $menuentry_id_option:

Kill user tty/pts sessions in Linux

Commands

w: show who is logged on and what they are doing
who: show who is logged on
tty: show current users pseudo terminal
ps -ft pts/1: get process id for the pseudo terminal
pkill: signal process based on name and other attributes

Whitelist IP addresses based on pre-filter policy

/etc/rspamd/local.d/multimap.conf:

  IP_WHITELIST {
      type = "ip";
      prefilter = true;
      map = "/${LOCAL_CONFDIR}/local.d/ip_whitelist.map";
 action = "accept";

Email server based on Dovecot, Postfix, MySQL, Rspamd and Debian 9 Stretch

MySQL database setup

Install MariaDB as a database management system DBMS

sudo apt install mariadb-server

Create a new database named srvmail for a mail server:

list messages trong 1 partition

kafkacat -b 10.5.69.6:9092 -t imap-2 -p 1

Metadata listing:

root@trangnth-kafka:/opt/confluent# kafkacat -L -b 10.5.6.6:9092 -t imap-2 
Metadata for imap-2 (from broker 1: 10.5.6.6:9092/1):

upgrade rabbitmq từ 3.6.x -> 3.8.16

backup lại user password

Listing users
monitor [monitoring]
openstack       [None]
guest   [administrator]

Flow of lua nginx module directives: https://openresty-reference.readthedocs.io/en/latest/Directives/
body_filter_by_lua documentation: https://github.com/openresty/lua-nginx-module#body_filter_by_lua
Following sample is from this site: https://groups.google.com/d/msg/openresty-en/5PWmL2f70x8/R2DUMsNUAgAJ

http { 
    proxy_cache_path /tmp/cache levels=1:2 keys_zone=cache:60m max_size=1G; 
    server { 
      listen 8080; 

      location /replace-body {

Quick cheat sheet of helpful tmux commands

tmux new - Create and attach to a new session.
tmux new -s NAME_HERE - Create and attach to a new session named NAME_HERE.
CTRL-b, d - Detach (i.e. exit) from the currently-opened tmux session (alternatively, tmux detach). Note, this means press and hold CTRL, press b, release both, press d.
tmux ls - Show list of tmux sessions.
tmux a - Attach to the previously-opened tmux session.
tmux a -t NAME_HERE - Attach to the tmux session named NAME_HERE.
CTRL-d - Delete (i.e. kill) currently-opened tmux session (alternatively tmux kill-session).
CTRL-b, [ - Enter copy mode, and enable scrolling in currently-opened tmux session. Press q to exit.
CTRL-b, " - Split window horizontally (i.e. split and add a pane below).

	# Create an access token for user "admin" with name "test-1234"
	# POST /users/{username}/tokens/{name}
	$ curl -i -u admin:admin -H 'Accept: application/json' -X POST 'http://127.0.0.1:12900/users/admin/tokens/test-1234?pretty=true'
	HTTP/1.1 200 OK
	X-Graylog-Node-ID: cd03ee44-b2a7-4824-be16-bb7456149dbd
	Content-Type: application/json
	Date: Mon, 08 Aug 2016 12:12:09 GMT
	Content-Length: 139

	{

	#!/usr/bin/perl

	use Digest::HMAC_MD5 qw/ hmac_md5_hex /;
	use DBI;
	use URI::Escape;
	use CGI;

	print "Content-type: text/html\n";

	my $q = CGI->new;