Active Directory on Evan Hoffman

Juniper SRX cannot use RADIUS authentication for client VPN?

Thu, 26 May 2011 13:29:31 +0000

Apparently using RADIUS authentication with Juniper SRX VPN is strange voodoo magic that’s never been tried before.

Renaming a single-label domain to a FQDN

Thu, 07 Apr 2011 17:56:54 +0000

Long ago – eons, perhaps – before I had anything to do with the Windows environment here, someone created the AD domain in my company as a single-label domain (e.g. instead of “example.com” our domain is just “example”). Over the years this has led to lots of “fun” on the part of Windows admins who’ve worked here as the implications of this choice became more apparent.

Since I inherited this system about a year ago, I haven’t really bumped up against any problems stemming from the single-label domain issue… until now. I recently attempted to add a new Windows 2008r2 file server to our DFS replication group/namespace. This totally failed for some mysterious reason. Well, I shouldn’t say “totally” failed, as I was able to add it to the DFS replication group, but unable to add it to the DFS namespace. In my attempt to debug the namespace issue, I deleted the namespace and attempted to recreate it, but just kept getting this error: The namespace cannot be queried. The specified domain either does not exist or could not be contacted.. I couldn’t do anything with the namespace - even clicking on it in the DFS Management console brought up an error. After some searching I found that this was likely due to having a single-label domain. I wasn’t sure why the error was happening even on Windows 2003 machines though, maybe joining a 2008r2 box to the domain made some schema changes? I tried a few suggestions like editing the hosts file but nothing seemed to resolve this.

Exchange 2010 Post-Upgrade weirdness: can't edit Mail Non-Universal Group or Security Group

Thu, 21 Oct 2010 22:29:38 +0000

Now that everyone’s been moved to Exchange 2010 we’ve started using the 2010 Exchange Managment Console/Shell exclusively which has revealed some weirdness. First, we created a new group in AD using an old script (which used LDAP) and created a Mail-enabled Global Security group. We put people in the group, and everything seemed to be working fine until it was discovered that users in the group couldn’t see the group in the Global Address List. Users not in the group had no problem seeing the group. Additionally, users in the group couldn’t see users added directly in 2010. This only appeared to affect the GAL; the users were able to send/receive email fine with the full SMTP addresses.

Exchange 2010 Post-Upgrade weirdness: can't edit Mail Non-Universal Group or Security Group

Thu, 21 Oct 2010 22:29:38 +0000

ldapsearch example on Active Directory

Thu, 26 Aug 2010 10:40:18 +0000

Just putting this here for safekeeping since I couldn’t remember the exact syntax.

[evan@ehoffman 10:35:50 ~]$ ldapsearch -x -LLL -D "ldapuser@example.com" -w password -b "OU=Users,DC=example,DC=com" -s sub -H ldaps://activedirectory.example.com "(sn=hoffman)" cn mail displayName samaccountname
dn: CN=Evan Hoffman,OU=Tech,OU=Users,DC=example,DC=com
cn: Evan Hoffman
displayName: Evan D. Hoffman
sAMAccountName: ehoffman
mail: Evan.Hoffman@example.com

Explanation: Connect to activedirectory.example.com using ldaps (SSL) with simple authentication, binding as ldapuser@example.com with password password; search for (sn=hoffman) within the OU=Users,DC=example,DC=com search base (branch), and search the subtree. Return the cn, displayName, and samaccountname fields.

ldapsearch on Active Directory

Thu, 26 Aug 2010 10:40:18 +0000

Just putting this here for safekeeping since I couldn’t remember the exact syntax.

[evan@ehoffman 10:35:50 ~]$ ldapsearch -x -LLL -D "ldapuser@example.com" -w password -b "OU=Users,DC=example,DC=com" -s sub -H ldaps://activedirectory.example.com "(sn=hoffman)" cn mail displayName samaccountname
dn: CN=Evan Hoffman,OU=Tech,OU=Users,DC=example,DC=com
cn: Evan Hoffman
displayName: Evan D. Hoffman
sAMAccountName: ehoffman
mail: Evan.Hoffman@example.com

Changing Active Directory Password in Browser through OWA 2010

Thu, 05 Aug 2010 11:29:41 +0000

A few months ago I was on a quest to figure out how to change my Active Directory password via a browser (for Linux/Mac users). I finally figured it out, but since I’ve been working on this Exchange 2010 migration I noticed one of the features of OWA (Outlook Web App) in Exchange 2010 is that you can change the AD password right in the browser from within the app:

Generate a report of Exchange mailbox sizes broken out by department and location

Thu, 29 Apr 2010 11:44:44 +0000

I found a script a few months ago that generated a CSV report of mailbox size, which included the Mailbox Name (usually the user’s name), size in Kbytes, number of items, which server it’s on, etc. This was very helpful, but I wanted to see which department within the company used the most space on the mail server, and the department wasn’t one of the pieces of data included in the report. It took a while but I figured out how to do LDAP lookups in vbscript and was able to add that info, so the report now has the user’s department, office location, and quota limit in it as well as the other fields. This makes it very easy to do a PivotChart in Excel to generate a pie chart of the size by department. The script is attached - change the extension to .vbs to run it. You’ll need to plug in your Exchange server and domain controller where the placeholders currently are.

Victory! Change Active Directory Password via LDAP through browser

Wed, 13 Jan 2010 13:51:43 +0000

I had to give up on PHP and go to Perl, but it turned out not to be so bad. Users can now change their Active Directory passwords via a self-service web page that doesn’t require admin credentials. The Perl code is below. Authentication to the script is done via .htaccess LDAP authentication, so the REMOTE_USER env variable is assumed to contain the user’s username (sAMAccountName) by the time this script is called. There is a simple check for $ENV{HTTPS} to ensure the script is called via SSL, and AD requires password changes to be done via ldaps, so the whole thing should be encrypted end to end.

LDAP-Active Directory authentication, Part 3

Fri, 08 Jan 2010 19:12:34 +0000

So I got everything working with .htaccess and AD/LDAP authentication. Just add LDAPVerifyServerCert Off to the httpd config to let Apache authenticate against an AD server with a self-signed certificate (without dealing with the annoyance of putting the cert on each Apache server).

With that piece of the puzzle largely solved, I moved on to another: how will users change their passwords (which are all stored in Active Directory)? For users running Windows this is pretty trivial – they can do it right in Windows when they’re logged into the domain. But what about Linux users? I figured the easiest thing to do would be to make a web form to do this. The user would login (with the http/LDAP auth I previously setup) and the form would ask for their password (twice) and update it in Active Directory. Sounds pretty simple to me. I think if this were OpenLDAP it probably would be, but being AD, it’s not.

Single sign-on with Linux clients and Active Directory LDAP, Part 2

Tue, 05 Jan 2010 18:45:55 +0000

Following up on my previous post, it turned out not to be as big of a deal as I’d originally expected to have Apache authenticate against AD and only allow users whose accounts weren’t disabled. In a nutshell, here’s what I did:

In your .htaccess file:

AuthBasicProvider ldap
AuthType basic
AuthName "AD LDAP Test"
AuthLDAPURL "ldap://activedirectory.example.com/OU=Users,DC=example,DC=com?sAMAccountName?sub?(!(userAccountControl:1.2.840.113556.1.4.803:=2))"
AuthzLDAPAuthoritative On
AuthLDAPGroupAttribute member
AuthLDAPBindDN ldapuser@example.com
AuthLDAPBindPassword password
Require ldap-group CN=Sysadmins,OU=Internal Groups,OU=Groups,DC=example,DC=com

The key here is this LDAP filter: (!(userAccountControl:1.2.840.113556.1.4.803:=2)). This is the bitwise “AND” of the userAccountControl field and the decimal number 2, which is Microsoft’s value for “account is disabled.” The codes are listed here: http://support.microsoft.com/kb/305144

Single sign-on with Linux clients and Active Directory LDAP, Part 1

Fri, 25 Dec 2009 00:20:15 +0000

One project we’ve been working on for a while is single sign-on across all our servers and other services (e.g. SVN repository, a few other things). One thing I wanted to avoid, I guess for mostly religious reasons, was reliance on a Windows instance for any of our production environment. The logical part of my brain knows that people build huge websites with Windows farms and AD, but my gut still doesn’t trust it. So what I wanted to do was setup OpenLDAP as a “slave” to an Active Directory “master” and have all the LDAP info propagate over the slave whenever any changes were made in the master. I’ve done this with DNS - setup Bind as a slave to an AD server and everything basically works as I expect in a Bind-Bind master/slave scenario. Well, it turns out that it doesn’t work like that when it comes to LDAP. Apparently AD doesn’t follow the RFC for LDAP (surprise!) so many things that would be expected to work with OpenLDAP won’t.