Saturday, February 11, 2012

Exchange 2010 Service Unavailable during SMTP transactions. Exchange Server is not accepting any incoming emails

I must say that my dear old friend Murphy paid me a visit this week. For those of you that are unaware of Murphy, you can get more information here . Basically Murphy's Law says that "Anything that can go wrong will go wrong"

Anyway, not to get side tracked. This week, one of my legacy Exchange Servers (Exchange 2003) broke down. Or that was what it seemed superficially. I am still trying to work through the migration of my Exchange 2003 servers to Exchange 2010. I still have a handful of users left on my legacy server and so am trying my best to move them across. As it happened, on this day, users on my Exchange 2010 started receiving Delay notifications when sending emails to users on Exchange 2003. Users on Exchange 2003 were also receiving the same when they tried sending emails to anyone on Exchange 2010 or to those outside the organisation.

I checked the queues and found that the Exchange 2003 queues were increasing with time and Exchange 2010 queues with emails destined to Exchange 2003 were suffering from the same fate.

My first reaction was that network issues might have cropped up, causing havoc between Exchange 2010 and Exchange 2003. Since Exchange 2003 was configured to deliver emails using Exchange 2010 for out-of-organization recipients, this theory  made perfect sense. But then when I checked the network connectivity between the two servers, there did not seem to be any problems :(

I then looked at the SMTP logs on Exchange 2003. To my surprise I found that one of the things logged was "Service Unavailable".  This meant that the Exchange 2010 CAS server was not receiving emails. I opened up a command line and tried connecting to the Exchange 2010 SMTP service, but after the handshake, I also received "Service Unavailable".

I RDP'd to my Exchange 2010 CAS server and checked the event logs. To my surprise I found that it was throttling the incoming email transactions. This was because the used diskspace on the disk that stores the queues had gone beyond 94%. This is known as BackPressure.

The simple solution was to find and remove all unnecessary files on the Exchange 2010 CAS server to bring the free diskspace up. As I looked through the eventlogs I saw Exchange reporting that the load on the resources had lessened and as such the limitations on the incoming queues was being removed.

Phew!. I forced the messages in the retry queues in both Exchange 2010 and Exchange 2003 and watched as the numbers reduced.

For those of you that would like to read more on Exchange 2010 Back Pressure, you can click through to the following articles
Technet - Understanding Back Pressure Back Pressure in Exchange 2010

I would recommend the MSExchange Article ;)

Sunday, February 5, 2012

Icons have disappeared from Desktop in Windows 7

Dont you just love it when simple things take more of your time than you actually anticipate? Well I had one of those moments just days ago.

The issue was that a user complained that when he turned on his machine in the morning, all his desktop icons mysteriously disappeared. I was a abit skeptical at first since he assured me that he had not changed anything. So I remotely connected to his computer, and found that he wasnt telling fibs. The icons had literally disappeared and all that was left was the desktop wallpaper.

At first I thought his user profile would be corrupted so thought to give it a simple test. I right clicked on the desktop and created a new text document. The process went through without any errors but the new icon failed to show on the desktop. I checked his user profile folder to see if the icon had been created. This can be found using the environment variable %userprofile%. So I looked at %userprofile%\desktop and found that a new text document had been created although it didnt show on the desktop. Ahem. Time for some head scratching.

Doing a quick search on the internet revealed the answer to me, and when I realised how simple it was, I could have almost kicked myself (but then I thought otherwise :) )

Anyways to get to the point, all I needed to do was the following

1. Right click on the Desktop and then click on View
2. A sub menu will show and there check to see if Show desktop icons is ticked. In my case it wasnt.
3. Click the Show desktop icons option and then when you return to the desktop, all your icons would have returned
4. You can click the Show desktop icons option again to hide the icons

Viola! Didnt I tell you that it was soo simple ;)

The above solution (and the image above) was copied from