In this article, we introduce two symptoms about the issue “DFS clients referred to off-site DFS server” and provide the solution to the issue.
Symptom One
You configure a domain-based Distributed File System (DFS) namespace. The namespace contains several namespace servers. When DFS clients access the namespace, they are referred to Off-Site DFS namespace targets.
Reproduce Steps
There are two Active Directory Sites, a DFS client and a DFS server named v-mayevm2 are in the same site. Another DFS server named v-mayevm3 are in the other site.
1. From the DFS client, access domain-based DFS Link target or folder target:
2. Run DFSUTIL /PKTINFO and note that the client access off-site DFS server v-mayevm3 link targets / folder targets, refer to figure 1.
Figure 1: Client access off-site DFS server
Troubleshoot
1. Right-click the namespace \\mandy.com\ns2, and then clickProperties. Check "referrals" tab to see if it is modified from “Lowest cost” (Figure 2).
Figure 2: Check Referrals
2. Check“Override Referral Ordering” in DFS Namespace server Properties to see if "First among all targets" is selected. If so, uncheck “Override Referral Ordering” (Figure 3).
Figure 3: Check Override referral ordering
3. IPv6 can cause the DFSN referral process to fail or be inaccurate, open the DNS Manager MMC snap-in and scan all the host (A) records for your domain's forward lookup zone. If you see any that report an IPv6 address and they are namespace servers or folder targets, you must validate your site configuration for IPv6 compatibility.
You configure a domain-based Distributed File System (DFS) namespace and DFS replication is enabled for target folders. When DFS clients access the namespace, they are referred to Off-Site DFS server targets.
Reproduce Steps
There are two Active Directory Sites, a DFS client and a DFS server named v-mayevm2 are in the same site. Another DFS server named v-mayevm3 are in the other site.
1. From the DFS client, access domain-based DFS Link target or folder target:\\mandy.com\ns1\target1
2. Run DFSUTIL /PKTINFO and note that the client access off-site DFS server v-mayevm3 link targets / folder targets, refer to figure 4.
Figure 4: Client access off-site DFS server
Troubleshoot
1. Right-click the namespace \\mandy.com\ns2, and then click Properties. Check "referrals" tab to see if it is modified from “Lowest cost” (Figure 5).
Figure 5: Check Referrals
2. Check “Override Referral Ordering” in Folder Target Properties to see if it is selected "First among all targets". If so, uncheck “Override Referral Ordering” (Figure 6).
Figure 6: Check Override Referral Ordering
3. As mentioned above, check if IPv6 cause the DFSN referral process to fail or be inaccurate.
1. The preferred method is to place a check mark next to "Internet Protocol Version 6 (TCP /IPv6)" on the IP Properties of the Adapter and reboot the server.
2. Configure Static IPv6 addresses on your DFS server and then define IPv6 Subnet/Site associations in Active Directory Sites and Services.
3. For those who have some aversion to having any IPv6 traffic hitting the wire there is a “supported” [not recommended by the Microsoft Product Group] way to disable outbound IPv6 using the DisabledComponents registry value as directed in KB929852.
More Information
DFS Referrals and IPv6: Outta site!
http://blogs.technet.com/b/askds/archive/2009/10/28/dfs-referrals-and-ipv6-outta-site.aspx
Tips for diagnosing why clients are referred to unexpected DFS namespace targets
http://blogs.technet.com/b/filecab/archive/2006/04/13/425169.aspx
DFS Override Referral Ordering, Messing with the Natural Order
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