How can I find out which server hosts LDAP on my windows domain?

Question

I am trying develop an application (C#) to query an LDAP server. I don't know the actual server named to query - is there a way to find out using standard windows tools or something in .net?

I've also heard rumors that having the server name (ldap://server/) is not always needed as long as I've got dc=domain,dc=com in my query string, but I've so far been able to work with it this way.

Any tips?

Thanks

Answer 1

AD registers Service Location (SRV) resource records in its DNS server which you can query to get the port and the hostname of the responsible LDAP server in your domain.

Just try this on the command-line:

C:\> nslookup  > set types=all > _ldap._tcp.<<your.AD.domain>> _ldap._tcp.<<your.AD.domain>>  SRV service location:       priority       = 0       weight         = 100       port           = 389       svr hostname   = <<ldap.hostname>>.<<your.AD.domain>> 

(provided that your nameserver is the AD nameserver which should be the case for the AD to function properly)

Please see Active Directory SRV Records and Windows 2000 DNS white paper for more information.

Answer 2

If you're using AD you can use serverless binding to locate a domain controller for the default domain, then use LDAP://rootDSE to get information about the directory server, as described in the linked article.