multihomed dc: (A) record disappears
cadman
master dc is win 2k3 x64 sp1 std, the other is win 2k sp4 std
this is a small operation, so our only 2 servers must be dc's
both machines have 2 nic's so one is set up for local network
(172.16.32.0) and the other is for a back end (10.0.0.0)
i did this so, for the sake of redundancy, i could use DFS replication
and the resulting traffic would not cause overhead on the local
network, as it goes on between the servers on the 10.0.0.0 link
through a crossover cable.
problem is this: win 2k's (A) record for the 172.16.32.0 network will
not stay in dns
win 2k's (A) record for the 10.0.0.0 network stays on
win 2k3's (A) record for the 172.16.32.0 network stays on
win 2k3's (A) record for the 10.0.0.0 network stays on
this is inconvenient because win 2k hosts iis intranet applications
and license servers we need
i have not set up WINS on this network, but then again it shouldn't be
a problem in this case
what do you think?
regards,
some_noob
Ace Fekay [MVP]
cadman <than...@very.much> stated, which I commented on below:
Honestly and with great recommendation, it is not recommended to multihome a
DC because of this reason and a few others. If you would like to keep the
multi-NICs on the DCs, here is a step-by-step to configure them (from one of
my previous posts). I hope it helps you out. If you feel it's much, just
disable one of the NICs or use teaming and use the main network and let your
routers handle the traffic to your other subnet.
/reprint:
********************************
Multihomed DCs, DNS, RRAS servers.
+++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++++++++++++++++++++++++++++++++++++++++++++++++++++++
Below are the manual steps in more detail, which I had outlined in the above
paragraph:
Honestly, multi-homed DCs are not recommended because of the associated
issues that can occur, as you've encountered. We usually recommend
purchasing an inexpensive Linksys, DLink, etc, Cable/DSL router to perform
NAT for you, take out the extra NIC off the DC, but still let the DC handle
DHCP (and not the router).
Little background on AD and DNS:
First, just to get this out of the way, if you have your ISP's DNS addresses
in your IP configuration (DCs and clients), they need to be REMOVED.
If the ISP's DNS is in there, this will cause additional problems.
Also, AD registers certain records in DNS in the form of SRV records that
signify AD's resource and service locations. When there are multiple NICs,
each NIC registers. IF a client, or another DC queries DNS for this DC, it
may get the wrong record. One factor controlling this is Round Robin. If a
DC or client on another subnet that the DC is not configured on queries for
it, Round Robin will kick in offering one or the other. If the wrong one
gets offered, it may not have a route to it. On the other hand, Subnetmask
Priortization will ensure a querying client will get an IP that corresponds
to the subnet it's on, which will work. To insure everything works, stick
with one NIC.
Since this DC is multi-homed, it requires additional configuration to
prevent the public interface addresses from being registered in DNS. This
creates a problem for internal clients locating AD to authenticate and find
other services and resources such as the Global Catalog, file sharing and
the SYSVOL DFS share and can cause GPO errors with Userenv 1000 events to be
logged, authenticating to shares and printers, logging on takes forever,
among numerous other issues.
But if you like, there are some registry changes to eliminate the
registration of the external NIC. Here's the whole list of manual steps to
follow.
But believe me, it's much easier to just get a separate NAT device or
multihome a non-DC then having to alter the DC. - Good luck!
1. Insure that all the NICS only point to your internal DNS server(s) only
and none others, such as your ISP's DNS servers' IP addresses.
2. In Network & Dialup properties, Advanced Menu item, Advanced Settings,
move the internal NIC (the network that AD is on) to the top of the binding
order (top of the list).
3. Disable the ability for the outer NIC to register. The procedure, as
mentioned, involves identifying the outer NIC's GUID number. This link will
show you how:
246804 - How to Enable-Disable Windows 2000 Dynamic DNS Registrations (per
NIC too):
http://support.microsoft.com/?id=246804
4. Disable NetBIOS on the outside NIC. That is performed by choosing to
disable NetBIOS in IP Properties, Advanced, and you will find that under the
"WINS" tab. You may want to look at step #3 in the article to show you how
to disable NetBIOS on the RRAS interfaces if this is a RRAS server.
296379 - How to Disable NetBIOS on an Incoming Remote Access Interface
[Registry Entry]:
http://support.microsoft.com/?id=296379
Note: A standard Windows service, called the "Browser service", provides the
list of machines, workgroup and domain names that you see in "My Network
Places" (or the legacy term "Network Neighborhood"). The Browser service
relies on the NetBIOS service. One major requirement of NetBIOS service is a
machine can only have one name to one IP address. It's sort of a
fingerprint. You can't have two brothers named Darrell. A multihomed machine
will cause duplicate name errors on itself because Windows sees itself with
the same name in the Browse List (My Network Places), but with different
IPs. You can only have one, hence the error generated.
5. Disable the "File and Print Service" and disable the "MS Client Service"
on the outer NIC. That is done in NIC properties by unchecking the
respective service under the general properties page. If you need these
services on the outside NIC (which is unlikely), which allow other machines
to connect to your machine for accessing resource on your machine (shared
folders, printers, etc.), then you will probably need to keep them enabled.
6. Uncheck "Register this connection" under IP properties, Advanced
settings, "DNS" tab.
7. Delete the outer NIC IP address, disable Netlogon registration, and
manually create the required records
a. In DNS under the zone name, (your DNS domain name), delete the outer NIC's
IP references for the "LdapIpAddress". If this is a GC, you will need to
delete the GC IP record as well (the "GcIpAddress"). To do that, in the DNS
console, under the zone name, you will see the _msdcs folder. Under that,
you will see the _gc folder. To the right, you will see the IP address
referencing the GC address. That is called the GcIpAddress. Delete the IP
addresses referencing the outer NIC.
i. To stop these two records from registering that information, use the
steps provided in the links below:
Private Network Interfaces on a Domain Controller Are Registered in
DNShttp://support.microsoft.com/?id=295328
ii. The one section of the article that disables these records is done with
this registry entry:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Netlogon\Parameters
(Create this Multi-String Value under it):
Registry value: DnsAvoidRegisterRecords
Data type: REG_MULTI_SZ
Values: LdapIpAddress
GcIpAddress
iii. Here is more information on these and other Netlogon Service records:
Restrict the DNS SRV resource records updated by the Netlogon service
[including GC]:
http://www.microsoft.com/technet/treeview/default.asp?url=/technet/prodtechnol/windowsserver2003/proddocs/standard/sag_dns_pro_no_rr_in_ad.asp
b. Then you will need to manually create these two records in DNS with the
IP addresses that you need for the DC. To create the
LdapIpAddress, create a new host under the domain, but leave the "hostname"
field blank, and provide the internal IP of the DC, which results in a
record that looks like:
(same as parent) A 192.168.5.200 (192.168.5.200 is used for illustrative
purposes)
i. You need to also manually create the GcIpAddress as well, if this is a
GC. That would be under the _msdcs._gc SRV record under the zone. It is
created in the same fashion as the LdapIpAddress mentioned above.
8. In the DNS console, right click the server name, choose properties, then
under the "Interfaces" tab, force it only to listen to the internal NIC's IP
address, and not the IP address of the outer NIC.
9. Since this is also a DNS server, the IPs from all NICs will register,
even if you tell it not to in the NIC properties. See this to show you how
to stop that behavior (this procedure is for Windows 2000, but will also
work for Windows 2003):
275554 - The Host's A Record Is Registered in DNS After You Choose Not to
Register the Connection's Address:
http://support.microsoft.com/?id=275554
10. If you haven't done so, configure a forwarder. You can use 4.2.2.2 if
not sure which DNS to forward to until you've got the DNS address of your
ISP. How to set a forwarder?
Depending on your operating system,choose one of the following articles:
300202 - HOW TO: Configure DNS for Internet Access in Windows 2000
http://support.microsoft.com/?id=300202&FR=1
323380 - HOW TO: Configure DNS for Internet Access in Windows Server 2003
(How to configure a forwarder):
http://support.microsoft.com/d/id?=323380
<==*** Some additional reading ***==>
More links to read up and understand what is going on:
292822 - Name Resolution and Connectivity Issues on Windows 2000 Domain
Controller with Routing and Remote Access and DNS Insta {DNS and RRAS and
unwanted IPs registering]:
http://support.microsoft.com/?id=292822
246804 - How to enable or disable DNS updates in Windows 2000 and in Windows
Server 2003
http://support.microsoft.com/?id=246804
295328 - Private Network Interfaces on a Domain Controller Are Registered in
DNS
[also shows DnsAvoidRegisterRecords LdapIpAddress to avoid reg sameasparent
private IP]:
http://support.microsoft.com/?id=295328
306602 - How to Optimize the Location of a DC or GC That Resides Outside of
a Client's
Site [Includes info LdapIpAddress and GcIpAddress information and the SRV
mnemonic values]:
http://support.microsoft.com/?id=306602
825036 - Best practices for DNS client settings in Windows 2000 Server and
in Windows Server 2003 (including how-to configure a forwarder):
http://support.microsoft.com/default.aspx?scid=kb;en-us;825036
291382 - Frequently asked questions about Windows 2000 DNS and Windows
Server 2003 DNS
http://support.microsoft.com/default.aspx?scid=kb;en-us;291382
296379 - How to Disable NetBIOS on an Incoming Remote Access Interface
[Registry Entry]:
http://support.microsoft.com/?id=296379
_________________________
+++++++++++++++++++++++++++++++++++++++++++++++++++++++
--
Ace
This posting is provided "AS-IS" with no warranties or guarantees and
confers no rights.
Having difficulty reading or finding responses to your post?
Instead of the website you're using, I suggest to use OEx (Outlook Express
or any other newsreader), and configure a news account, pointing to
news.microsoft.com. This is a direct link to the Microsoft Public
Newsgroups. It is FREE and requires NO ISP's Usenet account. OEx allows you
to easily find, track threads, cross-post, sort by date, poster's name,
watched threads or subject.
It's easy:
How to Configure OEx for Internet News
http://support.microsoft.com/?id=171164
Ace Fekay, MCSE 2003 & 2000, MCSA 2003 & 2000, MCSE+I, MCT, MVP
Microsoft MVP - Directory Services
Microsoft Certified Trainer
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