Friday, December 20, 2013

Configuring postfix to forward all email to a smtp gateway

SkyHi @ Friday, December 20, 2013


Suppose you want all your web servers to locally send all email (maybe from your contact forms, or whatever) to a real smtp gateway. If you're running postfix as your mta, this is quite easily to achieve.


In your file (usually /etc/postfix/ or /usr/local/etc/postfix/, specify your transport maps:
  1. transport_maps =  hash:/etc/postfix/transport  
And in your transport file (usually /etc/postfix/transport or /usr/local/etc/postfix/transport), specify your gateways per domain. This allows you to specify with regular expressions which emails go where. In this case, an asterisk specifies every domain (the transport file allows very complex setups, this is of course an extreme and trivial example):
  1. *      
Then invoke postmap to regenerate the transports db, and reload postfix:
  1. # postmap hash:/etc/postfix/transport  
  2. # postfix reload  
That should do it. All email generated in this host should now be forwarded to the smtp gateway. Remember to configure your smtp gateway to accept mail from all the hosts that will forward emails to it.

Volts / Watts / Amps Converter

SkyHi @ Friday, December 20, 2013
How to use this tool:
Watts = Amps x Volts
Watts is also known as volt-amps and is typically used in conjunction with AC power circuits. Fill in any of the two fields to find the value of the third.
Example 1
You have a 12 Volt power supply that delivers 1 Amp of current. Fill in the Volts and Amps fields to find the Watts.
Example 2
The AC24-40 power supply is a 24V AC power supply that can power up to 40 VA.
  1. Enter 24 under volts
  2. Enter 40 under watts
  3. Click calculate
  4. You get 1.66 in this example.
Thus, the AC24-40 can supply up to 1.6 Amps at 24V AC.