Inspeccionando la cola de correos sin entregar en Postfix

Por defecto se reintenta la entrega de los correos cada 5 minutos y se descartan (generando un correo de advertencia al remitente) si no ha podido hacerse transcurridos cinco días del envío. Podemos variar estos valores introduciendo los siguientes parámetros en el fichero de configuración principal (/etc/postfix/main.cf):

1
2
queue_run_delay = 600
maximal_queue_lifetime = 1d

Existen más parámetros relacionados con esta directiva en este enlace del manual de postfix.

Podemos inspeccionar la cola de postfix para ver que mensajes no ha podido entregar y la causa de ello en cualquier momento usando los comandos mailq o postqueue -p (ambos son equivalentes y proporcionan la misma salida aunque mailq es un comando mucho más flexible y potente con más opciones).


8A5E9E9225A 1708097 Mon Mar 7 22:40:01 a.hernandez@dominio.com.mx
(host dedrelay.securesvrfix.mx[208.109.80.210] refused to talk to me: 554 p3plsmtps2ded45.prod.phx3.securesvrfix.mx : HOSTING RELAY : d9OoamSM5zzCi : DED : You've rea
ched your daily relay quota - 209.109.80.210)
alatorre.c@dominio2.com
d.molina@grupomaas.com.mx8B012E9266E 67309 Mon Mar 7 17:55:15 a.hernandez@dominio.com.mx
(host dedrelay.securesvrfix.mx[208.109.80.54] refused to talk to me: 554 p3plsmtpout045.prod.phx3.securesvrfix.mx: HOSTING RELAY : d9JyaxC4eLF21 : DED : You've reach
ed your daily relay quota - 208.109.80.210)
sfernandez@dominio2.com.mx

el identificador del mensaje que nos permite ver mucha más información acerca del mismo, su estado y su contenido usando el comando postcat -vq seguido de dicho identificador. Por ejemplo, para inspeccionar el primer mensaje de la cola de aquí arriba:

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postcat -vq A3C3486137

También podemos decirle en cualquier momento a postfix que reprocese esos mensajes mediante los comandos postqueue -f o postfix flush. O podemos pedirle que reintente sólo uno de los mensajes de la cola usando el identificador que ya conocemos así:

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postqueue -i A3C3486137

Por último, para eliminar todos los mensajes en espera de entrega que están en la cola podemos usar el siguiente comando:

1
postsuper -d ALL deferred

Ten en cuenta que, en este caso, los mensajes serán eliminados sin que el remitente reciba ningún tipo de notificación de que no ha podido realizarse la entrega.

El siguiente comando elimina de la cola de correos el mensaje especificado.

postsuper -d D8D24E923E4

Actualizar distribución de Linux Ubuntu a la nueva versión

Actualizando Ubuntu

Antes de actualizar nuestra versión a la nueva, necesitamos que todos los paquetes de nuestro sistema estén al día. Para ello abriremos una ventana de Terminal y escribiremos el siguiente comando:

sudo apt-get update && sudo apt-get dist-upgrade

Este comando descargará e instalará los últimos paquetes disponibles que necesitemos. Continuaremos reiniciando nuestro sistema para que terminen de instalarse las actualizaciones pertinentes. Entonces usamos este comando:

sudo update-manager -d

Se nos mostrará la pantalla de Actualizaciones de Software que se encargará de buscar la nueva versión de Ubuntu disponible..

MIME Types for ClickOnce deployment

When you are hosting a ClickOnce deployment on a webserver, you need have certain MIME types defined so the server knows how to handle the files. You can host a ClickOnce deployment on any server regardless of the operating system. So you can host a ClickOnce deployment on an Apache server just as easily as a server running Microsoft Windows Server. You just need to set up the right MIME types.

When you install the .NET Framework, it registers the MIME types automatically. This is why you don’t have to set up MIME types if you install IIS on your desktop machine and test your deployments by deploying to localhost. Carrying that forward, if you have the .NET Framework installed on your server, the MIME types should already be registered.

This is generally one of the first things to check when you’re having problems downloading the deployment. A definite sign that your MIME types are not set up correctly is if your customers try to install the application and it shows the XML of the deployment manifest (the .application file) in Internet Explorer rather than installing the application.

Here are the basic MIME types you need for every ClickOnce deployment:

.application –> application/x-ms-application
.manifest –> application/x-ms-manifest
.deploy –> application/octet-stream

If you are targeting .NET 3.5 or .NET 4.0, you need these as well:

.msp –> application/octet-stream
.msu –> application/octet-stream

If you are deploying an Office application (VSTO add-in), you need this one:

.vsto –> application/x-ms-vsto

If you are deploying a WPF application, you need these:

.xaml –> application/xaml+xml
.xbap –> application/x-ms-xbap

Click one of these links to see how to set MIME types in IIS 6 or IIS 7.

If your application is hosted on an Apache webserver, you can set up your own MIME types by putting entries in the .htaccess file in the root folder of your deployment. The syntax for adding the MIME types is this:

AddType Mime-type file-extension

For example, for the first three MIME types above, you would add these lines to your .htaccess file:

AddType application/x-ms-application application
AddType application/x-ms-manifest manifest
AddType application/octet-stream deploy

You can create the .htaccess file simply by opening notepad or some other text editor and adding the lines above to it, and saving it with the file name of .htaccess. Then copy it to the root of your deployment folders, and those MIME types will work for that folder and all of its subfolders.

For more information than you ever wanted to know about .htaccess files, check out this article.

How to Install and Configure vsftpd on Ubuntu 14.04 LTS

FTP (File Transfer Protocol) is probably the most popular method of uploading files to a server; a wide array of FTP servers, such as vsftpd, and clients exist for every platform.

Pre-Flight Check

  • These instructions are intended specifically for installing the vsfptd on Ubuntu 14.04 LTS.
  • I’ll be working from a Liquid Web Core Managed Ubuntu 14.04 LTS server, and I’ll be logged in as root.

 

Step 1: Install vsftpd

Warning: FTP data is insecure; traffic is not encrypted, and all transmissions are clear text (including usernames, passwords, commands, and data). Consider securing your FTP connection with SSL/TLS.

First, you’ll follow a simple best practice: ensuring the list of available packages is up to date before installing anything new.

apt-get update

Then let’s install vsftpd and any required packages:

apt-get -y install vsftpd

Step 2: Configure vsftpd

For a refresher on editing files with vim see: New User Tutorial: Overview of the Vim Text Editor

Let’s edit the configuration file for vsftpd:

vim /etc/vsftpd.conf

Disallow anonymous, unidentified users to access files via FTP; change the anonymous_enable setting to NO:

anonymous_enable=NO

Allow local uses to login by changing the local_enable setting to YES:

local_enable=YES

If you want local user to be able to write to a directory, then change the write_enable setting to YES:

write_enable=YES

Local users will be ‘chroot jailed’ and they will be denied access to any other part of the server; change the chroot_local_user setting to YES:

chroot_local_user=YES

Exit and save the file with the command :wq.

Restart the vsftpd service:

service vsftpd restart

Step 3: Configure the User’s Home Directory

With certain version of vsftpd you may receive the following error: 500 OOPS: vsftpd: refusing to run with writable root inside chroot().

Not to worry! Create a new directory for the user receiving the error (user2 in this case) that is a subdirectory of their home directory (/home/user2). For example:

Fix permissions for user2‘s home directory:

chmod a-w /home/user2/

Make a new directory for uploading files:

mkdir /home/user2/files
chown user2:user2 /home/user2/files/

Activar SSL en Apache2 (Ubuntu 10.04)

# Instalamos Apache
sudo aptitude install apache2

# Habilitamos el módulo SSL
sudo a2enmod ssl

# Habilitamos la configuración SSL por default

sudo a2ensite default-ssl

# Reiniciamos el servidor
sudo /etc/init.d/apache2 restart

Ya con esto queda habilitado, puedes probarlo entrando al localhost con https://127.0.0.1
Para crear  nuestro certificado, debemos seguir los siguientes pasos

# Creamos las llaves

cd /etc/apache2

sudo openssl genrsa -des3 -out server.key 1024

# Creamos el certificado con la llave
sudo openssl req -new -key server.key -out server.csr

# Creamos nuestro certificado, contestando las preguntas que nos indique recordando la contraseña


sudo openssl x509 -req -days 365 -in server.csr -signkey server.key -out server.crt

#Cambiamos de carpeta la llave y certificado

sudo cp server.crt /etc/ssl/certs/
sudo cp server.key /etc/ssl/private/

# Abrimos el archivo de configuracion default-ssl

cd /etc/apache2/sites-available
sudo vim default-ssl

# reemplazamos y habilitamos la siguiente configuracion
SSLOptions +FakeBasicAuth +ExportCertData +StrictRequire
SSLCertificateFile /etc/ssl/certs/server.crt
SSLCertificateKeyFile /etc/ssl/private/server.key

# habilitamos el archivo

sudo a2ensite default-ssl

# Reiniciamos apache y listo!!
sudo /etc/init.d/apache2 restart

How to Install Microsoft Security Essentials on Windows Server 2012 and 2012 R2

You can install Microsoft Security Essentials on Server 2012, below is how to do so.

  1. Download a copy of MSE from Microsoft: http://windows.microsoft.com/en-us/windows/security-essentials-all-versions
  2. Right Click on the mseinstall.exe
  3. Click on Properties
  4. Click on the Compatibility tab
  5. Locate the Compatibility section
  6. Check Run this program in compatibility mode for
  7. Select From the drop down menu Windows 7
  8. Open a Command Prompt as Administrator
  9. Navigate to your Downloads folder (ie. cd C:Users%username%Downloads)
  10. Run mseinstall /disableoslimit and follow the installer prompts to install MSE on your Windows Server 2012.

Como crear un administrador mediante linea de comandos en linux Ubuntu?

Para poder agregar un nuevo usuario administrador (sudo), estos son los comandos a ejecutarse:

sudo adduser nuevousuario

Donde nuevousuario es el nombre del usuario que desea crear. Este comando crea el usuario, pero todo esto aún no le configura los permisos de administrador. Para dar ese permiso al usuario recién creado, seguidamente ejecute:

sudo adduser nuevousuario sudo

Esto asignara el usuario al grupo sudo, lo cual le permitirá trabajar como un administrador.

How to generate an SSH key on Windows using PuTTY?

You can generate an SSH key on Windows using the PuTTY SSH client. You can download PuTTY for free from this URL.

To generate a key with PuTTY, you should:

1. Download and start the puttygen.exe generator.

2. In the “Parameters” section choose SSH2 DSA and press Generate.

3. Move your mouse randomly in the small screen in order to generate the key pairs.

4. Enter a key comment, which will identify the key (useful when you use several SSH keys).

5. Type in the passphrase and confirm it. The passphrase is used to protect your key. You will be asked for it when you connect via SSH.

6. Click “Save private key” to save your private key.

7. Click “Save public key” to save your public key.

For more information on how to load the key and connect via SSH using PuTTY, please check this article.

TCP and UDP Ports for the vSphere Client

TCP and UDP Ports

Port

Purpose

Traffic Type

443 (Default)

HTTPS access

vSphere Client access to vCenter Server

vSphere Client access to ESXi hosts

vSphere Client access to vSphere Update Manager

Incoming TCP

902 (Default)

vSphere Client access to virtual machine consoles

Incoming and outgoing TCP, outgoing UDP

903

Remote console traffic generated by user access to virtual machines on a specific host.

vSphere Client access to virtual machine consoles

MKS transactions (xinetd/vmware-authd-mks)

Incoming TCP