Question:- Slow Email delivery

Hello Friends,
One of my Nizerian Client ask me thsi question

Dear Mr. Arun,

    How are you doing? I hope everything is going on fine.

I'm happy to inform you that I have successfully deployed exchange 2010 in our company; however, I have a little problem which I believe you can assist in resolving it. The problem is that when I send mail to a recipient within the same AD and even within the same database on the same MBX server, it takes an average of 10 to 15 minutes before the recipient sees it on his Outlook and even on OWA. Please what do you think I can do to ameliorate the situation?

    The scenario is as follows:

I have 5 exchange servers, EX1,EX2,EX3,EX4 and EX5.They are configured as HT,MBX and CAS.EX1 is located at head office and the other 4 span across geographical locations. And they are all connected to head office server thru vsat links. I have only one AD site and organization for the exchange environment and each location is configured with an exchange server plus another machine which is configured as AD integrated DNS and GC except the headoffice that contains 2 DNS (configured also as GC and DC).

Sometimes if a mail is originated from headoffice server and it’s meant to be delivered to a user at the same headoffice; I feel sometimes that this particular email traverses randomly across the regional servers(EX2,EX3 or EX4) thru vsat links before it finally comes back to headoffice for final delivery. And I feel this is what is causing the delay. This is what I feel but I want your contribution please. I’m so sorry for the inconvenience but it’s so important as management is not happy with me about it. Your swift response would be highly appreciated. Thank you.

Regards,

Mustapha

Nigeria

 Answer by Me:

Hello My Friend Mustapha,

Firstly sorry for late reply to you, I was busy in Training, I

 want to know firstly your organization entire scenario clear in my mind,

please tell me what is the configuration of your all the Exchange server, I mean hardware & OS, second what is your site link cost & did you configure that your all the sites Exchange email will be deliver using the head office, if is it, its the problem of may be your AD site replication & site link.

so please get back me ASAP. with all the answers.

secondly may be you have to configure the additional site link & HUB site for your head office & assign low cost for this Exchange site link with the SMTP protocol.

Please check also your HT queue viewer also for undelivered mail & try to resend ail again.

Waiting for your reply.