Gmail suffered an outage of more than one hour some time ago.
First impressions are to point out potential problems with Gmail. However, it’s actually a fine testament to the power of cloud.
The alternative to the cloud is to rely on a mail system created that relies on a good many more steps in the mail delivery process.
Typically, you have a mail client such as Outlook which connects to a mail server such as a Qmail or Outlook server. Outlook typically runs on a PC that is running Windows.
If any of these links fail, and almost everyone seems to have a tale of a Windows crash to tell, then so does the entire mail chain. Downtimes can be many hours especially if a technician has to be brought in. If you’re lucky it will be an expensive technician and you will have your email back up with just an expensive bill. At worst, you may end up with a junior web designer.
And this is the beauty of Gmail. You can sit back assured that a veritable army of some of the finest technical engineers on the planet are working relentlessly to get your problem fixed.
If you’re using a service like Outlook or Gmail you won’t even be aware of this.
However, if you send an email programmatically then you need to say who the Sender is. You usually do that using a Reply-To header. Unfortunately spammers have being doing this forever so, to avoid an email being labelled as spam, you’ll need to sign your email.
There are two main methods of creating Sender Signatures: DKIM and SPF.
DKIM (DomainKeys Identified Mail) has emerged from IETF (one of the Internet governing bodies) specifications and uses a signer’s public key which is published in the DNS. More here: http://en.wikipedia.org/wiki/DomainKeys_Identified_Mail
SPF (Sender Policy Framework) adds the list of authorized sending hosts for a domain in a TXT record. More here: http://en.wikipedia.org/wiki/Sender_Policy_Framework
For other methods see: http://en.wikipedia.org/wiki/Email_authentication