Migrator for Notes to Exchange & Coexistence Manager for Notes

configure domino for CMN

i want to configure domino for CMN (single name space domain.com), should I follow the following steps :
In the Domino Administrator, Configuration tab | Messaging section | Domains document | Foreign SMTP| Routing

fill in the tab (should be routed to) : Put the CMN IP



Or use this  steps

Configuration setting | Router/Smtp | Basic | and change local internet smart host with CMN IP

Please Advice 

Thank you