Mail Server Configuration
 

I'm using several mail boxes in Italy where I live. I run my personal mail sever (smtp) on my linux box and in the last period (a couple of years or something) sometime happen this to my mail messages:
1. my emails (I'm not a spammer) to my personal mail boxes are refused by the server (for example www.libero.it) with the following error code:
_______________________________________________________________________
host mailrelay03.libero.it[212.52.84.67] refused to talk to me: 554-mailrelay03.libero.it 554 Your access to this mail system has been rejected due to the sending MTA's poor reputation. If you believe that this failure is in error, please contact the intended recipient via alternate means.
_______________________________________________________________________
Nowaday I use kmail and mailx to send mail and postfix as MTA.
Bye and thanx for your time

generally you would look to use your ISP's relay host to forward email out to the net, if you can't find direct references to it try hitting smtp.myisp.com etc... and you may well find a relay host for the ISP's customers.