evolution mail sendind issue
 

Hi,
I am using evolution in RHEL4 AS , which is configured to send/receive mails. i am sure i have configured my mail servers correctly for POP/SMTP.
I am receiving mails without any problems. But am unable to send it . am getting the following error.

RCPT TO <to@to.com> failed:
<to@to.com>... Relaying denied.
IP name possibly forged [x.x.x.x].

but am able to send mails through webmail which is having the same IP , the one which evolution told is forged.

Suggestions are invited.