I am not an exchange expert, I work on Brocade load balancer. I set up LB for two exchange CAS servers. OWA is working fine getting proper load balance. 

I am facing issue in RPC services. When i enter exchange.millat.com.pk(LB Virtual IP) during configuring OUTLOOK account in windows. exchange.millat.com.pk is automatically converted to one of the original CAS server mail.millat.com.pk of MTL-EX3.millat.com.pk. 

I asked exchange engineer to set static port for Client server communication and for address book. Still i see one other tcp port in netstat -an -p tcp which changes in time to time. Could it be the public folder port?

Please can you experts guide me what could be the problem, why LB VIP is replaced by original CAS server FQDN when i hit check name during configuring outlook?

I am not an exchange expert, I work on Brocade load balancer. I set up LB for two exchange CAS servers. OWA is working fine getting proper load balance. 

I am facing issue in RPC services. When i enter exchange.millat.com.pk(LB Virtual IP) during configuring OUTLOOK account in windows. exchange.millat.com.pk is automatically converted to one of the original CAS server mail.millat.com.pk of MTL-EX3.millat.com.pk. 

I asked exchange engineer to set static port for Client server communication and for address book. Still i see one other tcp port in netstat -an -p tcp which changes in time to time. Could it be the public folder port?

Please can you experts guide me what could be the problem, why LB VIP is replaced by original CAS server FQDN when i hit check name during configuring outlook?

You have to set the RPCClientAccessServer value on the mailbox databases to the VIP as well

Set-MailboxDatabase <DB> -RpcClientAccessServer <VIPFQDN>
Note also that you will need to repair or create new Outlook Profiles for those that are still pointing the a specific CAS

Thanks for reply Andy, Got your point. As my client have 2 CAS servers and currently only one is entertaining all the clients. Currently he has only directed unused Mailboxdatabase towards VIP and have not directed other Mailbox by saying that it will stop my traffic. Will directing Mailboxdatabase towards VIP will stop clients from accessing CAS server directly? I think it will have no effect on the users which accessing CAS server directly.

I will ask him to point Mailboxdatabase of in use exchange towards VIP as well.

What do you make of that why exchange.millat.com.pk (VIP) is converted to mail.millat.com.pk( CAS FQDN) during configuring outlooking in windows?

Your help is much appreciated. 

So there are really 2 things you want to cover here.

The CAS Array and RPCClientAccessServer setting.

Create a CAS Array :

New-ClientAccessArray -Name name -Site site_name -FQDN (VIP FQDN>

Then set the RPCCLientAccessServer value on all the mailbox databases to the CAS Array FQDN ( Which is really the VIP FQDN.

Once you do that, going forward, the server name in Outlook will resolve to the CAS Array FQDN which is the VIP FQDN.

It will no change the existing Outlook profiles however. Their profile will continue to show the specific CAS unless you create or repair their Outlook profiles or the CAS they are connected to becomes unavailable.

More on CAS Array

http://blogs.technet.com/b/exchange/archive/2012/03/23/demystifying-the-cas-array-object-part-1.aspx

http://blogs.technet.com/b/exchange/archive/2012/03/28/demystifying-the-cas-array-object-part-2.aspx

Thank you so much Andy, understood. 

Just one more question, i want to set all ports static in exchange, as i have to configure them in load balancer as well. RPC uses 135 and two random ports. I asked him to configure static ports for this. He said we are not using address book but he configured static port for other service.

Now when i connect directly with one CAS server through outlook, I see that static port, 135 and two more random ports. I wonder what service is running on those, caz they changes time to time. 

I read i think one is for public folder and one could be for address book although we are not using address book service.

Can you confirm that? 

We 57763 static port. Now when i connect i see 57763, 135 but also see 18892, 36653 but last two changes time to time. They must be for public folder and address book right as i dont think exchange uses any more services.

Did you set static ports per:

http://social.technet.microsoft.com/wiki/contents/articles/864.configure-static-rpc-ports-on-an-exchange-2010-client-access-server.aspx