DNS Scavenging is a great answer to a problem that has been nagging everyone since RFC 2136 came out way back in 1997. Despite many clever methods of ensuring that clients and DHCP servers that perform dynamic updates clean up after themselves sometimes DNS can get messy. Remember that old test server that you built two years ago that caught fire before it could be used? Probably not. DNS still remembers it though. There are two big issues with DNS scavenging that seem to come up a lot:...

Issue In recent weeks we have seen a number of cases with intermittent file sharing connectivity to Windows Server 2008 servers. I wanted to get this information out so that people who may be experiencing the issue won't have to spend a lot of time tracking...

The DHCP database can be moved or migrated from a Windows Server 2003 server to a Windows Server 2008 server, or from one Windows Server 2008 server to another.  The information below details the necessary steps. Export the DHCP database from a server...

If you work with NLB in Multicast mode on Windows Server 2008, this is a must read for you, as you may run into this issue. Symptoms : You cannot connect to the NLB Virtual IP Address when NLB is running in Multicast Mode on Windows Server 2008 from machines...

A question that has come up from time to time is how and why Windows Vista and Windows Server 2008 detect a network as “unknown”. I hope the following explanation is helpful. Network Location Awareness or NLA is the service that determines what kind of...

Many Transmission Control Protocol/Internet Protocol (TCP/IP) networks use Dynamic Host Configuration Protocol (DHCP) servers that are administratively set up to allocate TCP/IP configuration information to clients on the network. DHCP is a TCP/IP standard...

Installation of Windows XP Service Pack 3 results in the Windows Firewall service being set to Automatic startup, regardless of its previous startup setting. After installing Service Pack 3 for Windows XP, you may be surprised to see that both the Windows...

Ask a DNS administrator and he’ll tell you there is no such thing as being “too careful” with DNS data! One of the dreaded things is to check the box for Auto Scavenging. A slight mis-configuration can lead to useful DNS entries getting...

In Windows, the DNS Client service is the client component that resolves and caches Domain Name System (DNS) domain names. When the DNS Client service receives a request to resolve a DNS name that it does not contain in its cache, it queries an assigned...

We have heard from a few customers about an issue with configuring Network Load Balancing (NLB) on Windows Server 2008 R2 virtual machines. This problem may occur with a Windows Server 2008 R2 virtual machine (guest) on Hyper-V or VMware. When you configure...

There is often confusion about how a computer chooses which adapter to use when sending traffic. This blog describes the process by which a network adapter is chosen for an outbound connection on a multiple-homed computer, and how a local source IP address...

The following question comes up from time to time and for various reasons. What is the expected name resolution behavior of the DNS client resolver on Windows XP or Windows Vista? This may be for a single or for multiple network interfaces. So I thought...

BALANCING ACT   Dual-NIC NLB Configuration with Windows Server 2008 NLB Clusters We’ve had a few calls from customers who have run into a particular issue when they’ve deployed NLB on a Windows Server 2008 cluster.  Most of them have had older...

In Microsoft CTS Network support, we frequently need to troubleshoot wireless connectivity issues. These issues are always made more difficult to resolve in instances where the wireless network is hidden. We recommend that customers do not use non-broadcast...

After running a Domain Name Rename of a domain that has Authorized DHCP servers in Active Directory, you may see the old server’s name still listed when you view DHCP Authorized servers. This will not prevent the servers from handing out IP Addresses...

We often have customers who want to better understand the resolution to their networking support issue and why what we did fixed their issue. Depending on the issue, this explanation may be quite involved and complex. This would be like asking the pilot...

When installing a new Windows 2008 server or upgrading an existing server to Windows 2008, the Computer Browser service is set to disabled by default. If you upgrade the Domain Controller that is assigned the PDC FSMO role or you move that role to a Windows...

What is an SNMP Trap? It’s nothing but an alert message with abstract information about an event sent from an SNMP agent to its configured SNMP manager. It notifies the administrators about an event that occurred in the SNMP agent. There is separate service...

Prior to SP3, the 802.1x service for XP is the Wireless Zero Configuration Service. This service handles the 802.1x needs for both wired and wireless connections. This has been problematic since not everyone uses wired 802.1x. Also, because the wired...

This post is meant to discuss the issues that can occur with Destination IP address selection and its affect on the DNS Round Robin process. What is Round Robin and Netmask Ordering DNS Round Robin is a mechanism for choosing an IP address from the list...

In this blog I’d like to give some information on what Named Pipes are, what a Named Pipes connection looks like, and some common things to look for if there is an issue. I do hope you have read RPC to Go v.1 and v.2 . It makes this much easier to understand...

The intent of this post is to give TechNet users a quick overview of RPC.  While it is sometimes hard not to delve into separate parts of RPC, I’ll do my best to keep it short.  Developers should use http://msdn.microsoft.com . Let’s...

Problem Description When a demand dial connection is setup between two RRAS servers each server receives an address from the pool of available addresses located on the server it is connecting to. When Server 2003 servers are used on both ends of the demand...

This post is an update to “ RPC to Go v.1 .”  I assume that you have read v.1 and have a basic understanding of how the RPC protocol works.  We’ll take a closer look at the architecture, End Point Mapper bind and the RPC bind...

When conducting network troubleshooting exercises on a daily basis, you start to take some of your simpler and more common tools for granted, until you lose them that is.  One of these basic tools for troubleshooting network connectivity issues is...