Malinda's Blog

Solution for NLB from ISA 2006

Problem with existing Windows load balancing technology is application awareness for example will take Sharepoint or Exchange Front-End load balancing server farm in case of failure of application like SMTP, Sharepoint services……etc. Windows NLB services cannot detect it. In that case still Windows NLB sends the traffic for problematical server because of that requests from some users will fail.

As a solution for that ISA 2006 provide application aware load balancing services for server farms, it can detect the application failure of particular server and stop sending request to that server until fix the problem.

This feature called “Web publishing load balancing” this illuminate use of Windows NLB in server farm, ISA Server 2006 will automatically balance the request stream coming from a remote user to an array of published servers.

This is how OWA publishing works;

Web load balancing features are automatically implemented when you publish Outlook Web Access and Outlook Anywhere. Outlook Web Access automatically selects a rule by using cookie-based load balancing. With cookie-based load balancing, all requests related to the same session (the same unique cookie provided by the server in each response) are forwarded to the same server. Outlook Anywhere uses source-IP based load balancing. With source-IP based load balancing, all requests from the same client (source) IP address are forwarded to the same server.

Read Only DC in Longhorn directory services

RODC is an Additional Domain Controller in a Domain, Host a Read only replica of Active Directory Services Database. Design primarily for branch office with fewer Users, poor Physical Security, relatively poor network bandwidth to hub server, no Dedicated Administrator.

RODC hold all object and attribute of a writeable DC, changes to any Object or attributes NOT Allowed and malicious user at branch locations cannot pollute or corrupt AD database.

RODC replicate only one way it pulls changes from writeable domain controllers.

It reduces the workload of bridgehead servers in the hub site and reduces effort to monitor replication.

By default, RODC will not store any password, except for its own account computer account and special krbtgt (Kerberos Ticket Granting Ticket) account, RODC is advertise as Key Distribution Center (KDC) for the branch then forward the authentication request to Hub if password not in cache.

Exchange server 2007 OWA access to internal portal server

As all of us now in Exchange 2003 and Outlook 2003 we can use Sharepoint portal server or services to store Exchange attachments, Outlook can send the mail with the URL for sharepoint document workspace.

This was a very valuable feature because it helps to reduce bandwidth usage for e-mails attachments but there was major bottleneck people who access the mails from outside the organization couldn’t able to access the internal URL.

Now Exchange 2007 comes up with new solution for this matter. People who access email from outside the organization allow to access internal portal server. Portal server can reside internal network without publishing through firewall but Exchange 2007 OWA enables access to internal portal server.

This is a cool feature which enables true product integration to increase productivity and ROI.