Exchange non-authoritive domain 2003 forward to 2013

Hi Guys,

I am trying to forward email from current domain to new domain both using the same email domain name.

I followed the setup in below link to make the exchange server non-authoritive and forward to new domain.

http://www.msexchange.org/articles-tutorials/exchange-server-2003/management-administration/Exchange-2003-SMTP-Namespace-Sharing.html

I know there is communication between current exchange server and new exchange server and I can manually send an email from current exchange server to new exchange server,  but when I send an email externally it looks to be looping with external mail filter and primary exchange server. So it looks to be using DNS to resolve email domain rather than SMTP forwarder.

Anyone have any ideas what might be creating this problem?

Thanks in Advance

Craig

Craig