How can i use dyndns with Ubuntu and send emails from it?
I want create a free domain with dyndns.com (mydomain.dyndns-at-home.com)
How can I link the domain with Ubuntu ?
How can I send emails from this domain? (firstname.lastname@example.org)
Setting up your box to be able to receive email is pretty easy if your ISP doesn't block it.
Getting the mail you send accepted is a lot more difficult, particularly since it sounds like you do not have a fixed address and thus no control of the reverse DNS records. Read through the questions here about "email and spam" to see all the various hoops you will have to jump through to not be classified as SPAM. Basically it is going to be impossible to get reliable delivery from a consumer/small-business broadband connection. It may be far easier to have your email hosted by someone else.
Anyway just install your favorite MTA, I prefer Exim since it is pretty simple to configure and also pretty flexible. Use
With this setup your emails can be assumed as being blocked by most receivers (making this just a headache) because:
If you're interested in learning email and related servers & protocols, you can setup a Rackspace Cloud Server 256MB for $11/month (plus bandwidth, should be small like another $1).
This way you can get a fixed IP, no ISP blocking, and control over the PTR (reverse DNS) cutting out most of the headaches. You just need a domain name.
One thing you'll probably need to do is remove the server's IP from Spamhaus' blocklist because some of the IP range was previously dynamic IPs. Just make sure you have the mail server set up at the point because Spamhaus will check to make sure.
As Rob said, you won't be able to send directly from your home connection. The cheapest solution is to simply relay your email through your ISP's mail servers. If they won't accept email with a sender domain that isn't theirs then services like MailHop Outbound from DynDNS will work (more here on the DynDNS SE community).
If your ISP does block 25/TCP inbound then services like MailHop Relay from DynDNS will allow you to work around that.