Hi, One user of my company sent an e-mail to another company, but after 24h he received a NDR with following message: user@outraempresa.com on 18-06-2008 21:34 You do not have permission to send to this recipient. For assistance, contact your system administrator. <exchangeserver.mydomain #5.7.1 smtp;501 5.7.1 user@mydomain... Sender IP must resolve> I think that I have MX Record and DNS Reverse configured. How can I verify these? How can I fix this problem? Regards, Bruno Trindade

does that user is listed in a distribution group ? or it is a mail-contact ? try to un tick the "require that all senders are authenticated" inside the message delivery restriction setting in a distribution group tab.

Albert Widjaja T. wrote: does that user is listed in a distribution group ? or it is a mail-contact ? try to un tick the "require that all senders are authenticated" inside the message delivery restriction setting in a distribution group tab. It is a mail contact. I think the problem is with DNS Reverse.

Hi, This issue may occur if the remote domain server enable the reverse DNS look up but failed to resolve your outing IP address of the exchange server. Please make sure your IP address can be resolved to domain name without issue by the remote domain server. Thus, we need to ensure the PRT record existed in the DNS. Thanks Allen