Hello, I have setup Exchange 2013 with below scenario:

Domain Controller WS2012R2: "company.com", NIC1-Internal Network: 10.10.10.2. NIC2-External Network: 192.168.1.10 (NAT to Public IP)

Exchange Server 2013 WS2012R2: "company.com", NIC1-Internal Network: 10.10.10.3, NIC2-External Network: 192.168.1.11 (NAT to Public IP)

Mail-flow in working fine for internal network and I can send e-mails for external domains, However, it takes a few hours to receive anything from external domains. 

Can anyone please explain what can cause this issue?

And also, provide me a list of all necessary DNS records to set on my Public and Local DNS based on the scenario above. I want to make sure they are all added correctly.

Thanks!

• Edited by Hamed Da Saturday, April 25, 2015 6:02 AM

Hi ,

To identify the mail delay from internet please make use of the mail headers in anyone of the received delay mail.So that headers will reveal on which hop the mail has been delayed .

Please make use of the message tracking logs to find out the delayed hop.

DNS Records in external world : 

MX record 

PTR record 

SPF record 

A record  - For autodiscover,owa,active sync,pop ,imap and web services in exchange.

DNS Records In Internal DNS : 

For your SMTP namespace you can have a DNS zone and on that you can create Host A record for the services like autodiscover,owa,active sync,pop ,imap and web services to resolve inter