Hi all, two companies (A and B )share GAL through gal sync (IIFP). forest trust built. (winows 2003 SP2, exchange 2003/2007) Now, a company A user send email to the distribution group that belongs company A forest, some users from company B receive it too. Company B user is not in this DG that belongs to companyA. How would this happen? verey strange? How should I troubleshoot this? Thank you.

Are you sure the DL in question is what's in the GAL and not from the users PAB?[string](0..33|%{[char][int](46+("686552495351636652556262185355647068516270555358646562655775 0645570").substring(($_*2),2))})-replace " "

yes. That's former company A's distribution group. could it be the nested group that has the same name as companyB?

double checked it again. the company B usres are not in the DL? What could it be? How should I troubleshoot this?

I'd start with message tracking. [string](0..33|%{[char][int](46+("686552495351636652556262185355647068516270555358646562655775 0645570").substring(($_*2),2))})-replace " "

Thanks. I did and I can see the message route from company A exchange server to companyB exchange server. But, I can not see the details as I got the message "The tracking database on server2 (companyB's exchange server) is not available or the the message has left the exchange organization" What should I try next?

You'll have to resume the tracking from the Exchange server at Company B, since it appears that's where the DL expansion took place. Track it by the messageid.[string](0..33|%{[char][int](46+("686552495351636652556262185355647068516270555358646562655775 0645570").substring(($_*2),2))})-replace " "