SMTP relay problem
 

Hi all. I am using redhat 7.1 with sendmail 8.11.2-14. When i tried to send mail using Outlook Express client, it gave the below error message. How can i go abt solving it ??

If i entered the ip:10.79.222.3 on the server host file or /etc/mail/access file, then i can send the mail out. But if i were to
send mail from different external access, the ip address may differ.
Any ideas ??


The message could not be sent because one of the recipients was rejected by the server. The rejected e-mail address was 'test@yahoo.com'. Subject 'zzz', Account: 'server mail', Server: 'xxx.abcd.com', Protocol: SMTP, Server Response: '550 5.7.1 <test@yahoo.com>... Relaying denied. IP name lookup failed [10.79.222.3]', Port: 25, Secure(SSL): No, Server Error: 550, Error Number: 0x800CCC79