Tech Blog

So today I was working at a site that has a single Exchange 2010 server that forfills all the Exchange roles (I know….) which happened to fall on its ass.

First thing I did was check the Exchnage services which were in a state of “starting” which is never good and then I went to the registry and found:

MSExchange ADAccess, EventID 2141
Process STORE.EXE (PID=2996). Topology discovery failed, error 0x8007077f

MSExchange ADAccess, EventID 2142

Process MSEXCHANGEADTOPOLOGYSERVICE.EXE (PID=1760). Topology discovery failed, error 0x8007077f

Here’s a few screen shots:

As well as a few more related to AD.

After some investigation I found out that a new DC in a new site had been created for some DFS replication amongst other things.

As the system could start the Microsoft Exchange Active Directory Topology service (until it failed and is restarted by dependent services), Exchange’s other services were also triggered, leading to almost indefinitely restarting services as configured in their corresponding service recovery actions sections.

So next up is to look at Active Directory Sites and Services:

And as you can see from the screen shot the subnets are missing, which is going to cause issues as the new DC is on a different subnet.

When Exchange can’t determine in which site a computer belongs, the function DSGetSiteName, used to retrieve the current site, returns an error 1919 0x77f (ERROR_NO_SITENAME) which in turn kills off Exchange.  You can test this by running nltest /dsgetsite in a command prompt or by having a look at  HKLM\System\CurrentControlSet\Services\Netlogon\Parameters\DynamicSiteName.

To solve the issue you can do any of the following:

1. Making the site association static using a registry key, which isn’t a best practice. If you must, set registry key HKLM\SYSTEM\CurrentControlSet\Services\Netlogon\Parameters\SiteName(REG_SZ) to the desired site name;
2. Adding proper subnet definitions;
3. Remove the new site.

Finally give Exchange a  bounce and BOOM.

Note that the NetLogon service determines site association membership at startup and every 15 minutes. The Microsoft Exchange Discovery Topology service maintains this information by caching the information in the msExchServerSite attribute of the Exchange server object, in order to reduce load on active directory and DNS. Therefore, you might need to wait or restart Microsoft Exchange Discovery Topology if you want to renew site association membership.

So a customer recently had issues where their users were typing the wrong URL and then complaining that they couldn’t log in.

To try and help (and can you really help users who don’t know their own URL?, I mean come on you work there a minimum of 37 hours a week) this issue I suggested adding a simple logo to the OWA home page, i.e. go from:

To

So I logged onto each of the four Exchange 2010 Client Access Servers navigated to:

 C:\Program Files\Microsoft\Exchange Server\V14\ClientAccess\Owa

And then chose the folder that matched the version of Exchange in our case: 14.342.3 (to check open Exchange 2010 console and click help and About Exchange Server 2010):

 C:\Program Files\Microsoft\Exchange Server\V14\ClientAccess\Owa\14.2.342.3\

Next I found the logo file I needed to modify, specifically:    lgntopl.gif

Edited the gif to look like the above (well not exactly like that) and replaced the on each Client access server.

Navigated to the web and BAM…… didn’t work!

So next I checked the exchange console > Server Configuration > Client access

And noticed the version was actually on Build 247.5, so decided to swap the gif in the matching location:

 C:\Program Files\Microsoft\Exchange Server\V14\ClientAccess\Owa\14.2.247.5\

And BAM, still didn’t work!!

Well at this point I was annoyed….

So remembered (and called myself various names) that we have a Threat Management Gateway that presents OWA to the internet.

So after a quick search on the TMG and a few clicks of the Exchange OWA web listener I found:

 C:\Program Files\Microsoft Forefront Threat Management Gateway\Templates\CookieAuthTemplates\Exchange\HTML

Swapped the gif file and BAM, still didn’t work!! ARRRRGGGHHH

Here’s the clincher, I had to restart the TMG service!! Unfortunately TMG caches these pages and restarting the service is the only way to clear the cache as far as I know.

So BAM it works!!  🙂