Is there a way to find Active Directory on the network without providing any info in C#?

Question

I'm looking for a way to find Active Directory on the network (probably thru DNS/DHCP settings assigned) and then trying to access it, getting all the things like AD servername, BaseDN or domain name from within a code without asking user to provide information about his network. Is there a way to go?

    private  string strADServerName = "SERVERAD";
    private  string strBaseDN = "DC=DOMAIN,DC=COM";
    private  string strAccountFilter = "sAMAccountName";
    private  string domainName = "DOMAIN";

score 2 · Accepted Answer · edited Mar 04 '13 at 13:14

2

When you install a Active-Directory you need a Dynamic DNS (DDNS). During his installation AD registers information in the DNS, as you can see in the following capture. On a given Windows computer the WMI class win32_ComputerSystem can provide you the domain name.

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You can see here under the detail of _ldap entry :

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This SRV entry provide DNS address and port of the domain controllers of your domain. _ldap entry can have multiple values as you've got multiple domain controllers in your domain.

Using NSLOOKUP.EXE tool, you can get this information as shown here under :

> set type=SRV
> _ldap._tcp.dom.fr
Serveur :   UnKnown
Address:  192.168.183.100

_ldap._tcp.dom.fr       SRV service location:
          priority       = 0
          weight         = 100
          port           = 389
          svr hostname   = wm2008r2ent.dom.fr
wm2008r2ent.dom.fr      internet address = 192.168.183.100

If you don't know the domain you can just query for _ldap._tcp like in the sample above :

> _ldap._tcp
Serveur :   UnKnown
Address:  192.168.183.100

_ldap._tcp.dom.fr       SRV service location:
          priority       = 0
          weight         = 100
          port           = 389
          svr hostname   = wm2008r2ent.dom.fr
wm2008r2ent.dom.fr      internet address = 192.168.183.100

On the C# point of view, I am not sure that the class System.Net.DNS allow you to query SRV records. You can find in this codeplex entry DnDNS assembly seems to do it.

edited Mar 04 '13 at 13:14

HasaniH

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answered Apr 28 '11 at 05:08

JPBlanc

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I know about nslookup method .. although you still have to type _ldap._tcp.dom.fr don't you? so you have to know what you're looking for ? – MadBoy Apr 28 '11 at 06:18
win32_ComputerSystem can give you the "dom.fr" part. – JPBlanc Apr 28 '11 at 06:55
Will it supply that on non-domain computer as well ? – MadBoy Apr 28 '11 at 07:03
Of course not. What do you really want to do ? discover AD on a network from nothing ? – JPBlanc Apr 28 '11 at 07:07
Well yes. I have computer which isn't in domain but I need it to be able to discover Active Directory when it's attached to the network. So that in program I will write I won't have to type in the domain name and so on but I could just pick it from choice menu and program would do the rest. Considering that DHCP assings me DNS which is also Active Directory this should be doable. – MadBoy Apr 28 '11 at 07:14
with '_ldap._tcp' if the 'DNS suffix for this conexion' is correctly parametered in the IP stack it should be doable. – JPBlanc Apr 28 '11 at 07:32

Is there a way to find Active Directory on the network without providing any info in C#?

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