Ant Drewery

If you have a small to medium sized Exchange environment the chances are you’ll have a single point for inbound email and your MX records will look something like this:

MX 10 smtp.mydomain.com
MX 20 smtp.myisp.com

Your primary inbound point would be your Internet connection and your secondary is often your ISP who provides a store and forward service if your server or Internet connection is unavailable.

If you have a larger environment you may have more than one mail gateway (we have 2 in the US, 2 in the UK and 1 in Australia) and might want to load balance inbound email between them. There are two possible ways to achieve this.

The first method is to use a concept called DNS round-robin. Here you would create A records for your gateways each with it’s own IP address but using the same name. For example:

A smtp.mydomain.com 212.111.212.111
A smtp.mydomain.com 212.111.212.112
A smtp.mydomain.com 212.111.212.113
A smtp.mydomain.com 212.111.212.114

(I made the IP addresses up)

The MX record would then be:

MX 10 smtp.mydomain.com

The second method is to give all the MX records for your gateways the same value. You would have individual A records and your MX records would look like this:

MX 10 smtp1.mydomain.com
MX 10 smtp2.mydomain.com
MX 10 smtp3.mydomain.com
MX 10 smtp4.mydomain.com

Whilst none of these methods will give you 100% perfect load-balancing they are effective in distributing the load between gateways. We have also experimented with Windows Network Load Balancing but have found that it doesn’t play well in our Cisco routed environment. From the Microsoft document “Network Load Balancing : Configuration Best Practices for Windows 2000 and Windows Server 2003″:

Some routers require a static ARP entry because they do not support the resolution of unicast IP addresses to multicast media access control addresses. For example, Cisco routers require an ARP (address resolution protocol) entry for every virtual IP address. While Network Load Balancing uses Level 2 Multicast for the delivery of packets, Cisco’s interpretation of the RFCs is that Multicast is for IP Multicast. So, when the router doesn’t see a Multicast IP address, it does not automatically create an ARP entry, and one has to manually have to add it on the router.

Due to the critical nature of our email usage a major virus outbreak on our Exchange servers would probably cost me my job. So to help me sleep easier at night I use layers of defence. We run one anti-virus product on our MailSweeper gateway servers and a product from a different vendor on all of our internal Exchange servers. The concept of using different products is if one vendor doesn’t have a definition available to detect a certain virus the other vendor might. This layered approach gives us a fighting chance if a virus gets past MailSweeper or hits us from the inside via a webmail service.

As additional precaution we set the automatic definition updates to be as frequent as possible and also block any executable attachments (internal & external).

We saw a sharp increase in the amount of viruses caught by our MailSweeper servers yesterday, double the usual volume. Here are the top 10 viruses that we’ve caught so far this month:

1 - W32/NetSky.P@mm
2 - Email-Worm.Win32.NetSky.q
3 - Exploit.HTML.Iframe.FileDownload
4 - Email-Worm.Win32.Sober.y
5 - HTML/IFrame@expl(exact)
6 - Net-Worm.Win32.Mytob.cg
7 - Net-Worm.Win32.Mytob.c
8 - Trojan-Spy.HTML.Bayfraud.hn
9 - Email-Worm.Win32.NetSky.r
10 - Net-Worm.Win32.Mytob.ab

I mentioned mind mapping in an earlier post so I thought I’d provide a bit more information on what I use it for. I was introduced to the concept by a colleague a few months ago and now I’m hooked. For me it’s a very visual way of thinking that suits my thought process. My main uses are:

A Google search on “mind mapping” will result in a plethora of links to sift through at your leisure. If you’re looking for an easy to read book to get you started then I’d recommend “The Mind Map Book” by Tony & Barry Buzan. Tony Buzan originated Mind Maps in the late 1960’s.

I currently use MindJet’s MindManger Pro as my mapping software of choice. You can download a 30 day free trial.
If you’re into open source software then there’s an excellent prodcut called FreeMind.

I came across a fantastic Firefox plugin via Jake Luddington’s newsletter. It’s called IE Tab and is available from http://ietab.mozdev.org.

I use Firefox as my primary browser but it doesn’t play nicely with some of the sites/applications that I use e.g. Outlook Web Access. This plugin allows you to define a list of sites/pages that you would normally view in IE. Then, when you type the URL into Firefox it automatically opens a tab which is an embedded Internet Explorer page. Very cool and so far works with all my usual suspects.

I came across this post on the jkOnTheRun blog. This is great news as I’m a big fan of mind mapping and use both MindManager and Google Desktop Search.
jkOnTheRun: New MindManager plugin for Google Desktop Search

Microsoft have announced that Exchange 12 is to be 64 bit only:

To help customers take full advantage of the power of 64-bit computing, products including Microsoft® Exchange Server “12,” Windows Compute Cluster Server 2003, Windows Server™ “Longhorn” Small Business Server, and Microsoft’s infrastructure solution for midsize businesses, code-named “Centro,” will be exclusively 64-bit and optimized for x64 hardware.

You can read the full press release here.

It’s not something that I’m going to worry too much about at the moment but I will be making sure that any new hardware we buy will be compatible with the next version of Exchange.

Ben Winzenz gives some detail on what hardware will be compatible in his blog posting.

I’m often asked my thoughts on the individual mailbox backup feature (aka Brick Level backups) in some third party backup products. If it’s for Exchange 2003 my response is always “don’t bother”.

Firstly I would never recommend using it instead of the standard database and log backup as this could leave you hurting in a true DR situation. That’s not to say that you couldn’t use Brick Level backups to recover from a corrupted store or dead server but it’s going to cause you some pain. The restore is going to take longer, you’re going to lose single instance storage and you’re not going to be able to replay the logs to get you back to the point of failure, resulting in lost email.

So secondly, if you’re going to use it as an additonal backup method, you’re going to double the amount of storage required and increase the time taken for your backups.

So what would I recommend? This:

Now if you accidentally delete a mailbox, for the next 30 days you can re-associate it with a user account via Exchange System Manager.

So what do you do if someone says they’ve deleted an important email? If they followed the normal deletion method you can highlight Deleted Items in Outlook and use Recover Deleted Items from the Tools menu. If they shift-deleted from a folder or moved the item to a PST file (which is actually a copy & delete) you’ll need to use the DumpsterAlwaysOn reg hack to enable Recover Deleted Items for other mailbox folders and public folders.

If you need to recover an item or mailbox after the 30 day retention period then you can restore the appropriate mailbox store to a Recovery Storage Group and use the Mailbox Recovery Centre in ESM or Exmerge to get back what you need.

Ok, so we’ve successfully upgraded our first cluster to Exchange 2003 SP2. Prior to the upgrade both nodes were running Windows 2003 SP1 and Exchange 2003 SP1 and fully patched. Here’s the exact process that we followed:

I’m a big fan of Windows Media Center and have a system that I’ve put together myself running in my front room. This week I bought a Microsoft Media Center Keyboard to replace the existing wireless keyboard I was using. I have to say that I’m impressed.

It uses the same IR receiver as the MCE Remote. That’s a good thing in my opinion as it eliminates the need for a separate receiver to be hanging off your box. For those of you that are concerned about IR being line-of-sight don’t be. I pointed the keyboard in every direction I could think of in the far corners of my living room and had no problems at all. My previous keyboard used RF and the range left a lot to be desired.

The keyboard has a very high build quality and a nice weight to it. It has all the buttons from the remote so you can happily control your Media Center with it.

My only citiscim is the ‘nipple’ can be a little hard to control, even when you’ve dialled down the pointer speed in Control Panel. I guess I’ll get used to it. The built in trackball on my previous keyboard was superior in my opinion. However, this is a minor point and would not put me off recommending the keyboard to anyone.