Error when sending mail to an external mail server from Postfix on CentOS

I just installed Postfix. i have not yet done any configuration on it. Each time I try to use it to sendmail from another application, it keeps telling me that COnnection was refused from the ip I want to connect to. This is the error I get

[root@localhost /]# telnet mail.abuse.org Trying 69.43.160.153... telnet: connect to address 69.43.160.153: Connection refused telnet: Unable to connect to remote host: Connection refused

COuld someone please help me the problem

From serverfault yankitwizzy

• By default, IP tables might be blocking your connection. Try:

  /etc/init.d/iptables stop
  

  And the retry to telnet to your ip on port 25 like this:

  telnet localhost 25
  

  From Reinoud van Santen