Question : how configure 2 mailbox to one user

in my company i have exchange 2003 now few user have mailbox for example xxx.xxx.co.il and this users have another mail in outside  like xxx.xxx.com i want to configure if some send mail to the com domain the mail come directly to ther mailbox with co.il domain how i configure it in the co.il domain?

Answer : how configure 2 mailbox to one user

The mail server depends on MX records configured to a particular domain name.
MX records tell the email on which server they need to go.

In your case MX records are configured for both of the domains on 2 different domain names (.com & .co.il) So sending email to .com email id won't be received by .co.il email server.

Now when a mail is received to .com email id, it wont automatically go to .co.il email id, unless you choose 1 of the option below:

1. Configure a email forwarding on .com email server to forward all email for that user email id to goto .co.il email. (optional, delete a copy after sending)

2. Configure a POP3 Connector in .co.il exchange server to pull email from .com email id every 5 minutes (doing this will delete the copy from .com email id, this is the way exchange pop3 connector works, unless you want to go for 3rd party connector which can do everything) This option also requiers that .com email id has pop3 option enabled.

Let me know if you have doubts from my answer.