Rob Golding

Okay, so the network that I have been managing for some time now has just undergone a pretty big redesign. It’s actually a home network, but it spans 2 sites – my house and my friend’s house. They are “joined” by a site-to-site VPN connection, which gives us a load of benefits like easily sharing photos, programs, and an AD/Exchange forest.

Up until recently, the network was running with just one physical server at each site, we shall call them Site A and Site B, each with VMware Server installed. Both servers were configured almost identically, with the host machine running AD (Active Directory) and Exchange 2003, and a VM running ISA Server 2006 for the firewall/VPN. Another VM was used for hosting some websites in the Perimeter network.

The redesign saw one new server in at Site A and two new servers at Site B – although the main server at Site A has been upgraded significantly. The new servers were installed to take the firewall away from the Virtual Machine to a physical one – as this is much more secure. Also, the second new server at Site B hosts Exchange, while this is now on a VM at Site A.

This network doesn’t support many clients or users, but it used mostly for educational purposes. For that it is perfect. We have a multi-tree forest AD configuration, with one domain for each site (or each house!), and one Exchange organisation spans the entire forest, with one Exchange server at each site. This also helps if one server/network is down, as the other will pick up the email for both sites – so we have a failsafe if one network is having problems.

I have published a “public” version of the network diagram, with external IP addresses/names removed, just in case anyone might find it interesting. Just click the thumbnail for a fullsize version.

As you may have noticed, I’ve used the names of gods from Greek and Roman mythology for the servers. The web servers are the oldest ones there so they haven’t been renamed yet. Maybe an exiting project for the future!

Both networks now have a 20mb/784kb internet connection (up/down), so the VPN link is essentialy 784kb/sec both ways. That’s pretty good for things like AD replication, but not brilliant for sharing files and photos.

The active directory is the aspect of the network I am most proud of. Since the rebuild it has been working flawlessly, although I am forever looking at ways to expand the directory. The DC at each site hosts a DNS zone for both domains, which provides redundancy for DNS if one DC is down, and both servers hold a copy of the Global Catalog. This allows for fast directory searches from both sites, and gives each Exchange server a GC to look to.

The forest is split logically, as well as physically, into sites. This allowed me to easily alter the replication schedule for the Domain Controllers, although I decided to leave this at hourly intervals, as I saw no reason to alter this value.

Hopefully the AD forest and network infrastructure will provide a solid base to expand on, and I will post about any major additions to the network. At present the clients consist of XP and Vista machines, but we are soon to aquire a new desktop, which will be running Vista, that will make a nice addition to AD.

Up until yesterday, my Exchange server was my DC - they were one and the same. As anyone will tell you, this isn’t a particularly desirable configuration. For one thing, if you want to demote the DC, you have to uninstall Exchange first, and that means lots of migration and replication and…well it’s not very nice!

So, I finally took the big step, and migrated all the Exchange data off the DC, and uninstalled it. So now I have a seperate Exchange server, which means tons more RAM free on the DC.

This also allowed me to install something I’ve been looking at for quite some time now - WSUS 3. I now realise how useful this piece of software can be. I am only managing about 5 computers, plus a few servers, but this makes keeping the machines up-to-date so much easier. Plus, you get lovely graphs like this:

Also worth mentioning, is that the Exchange server I’ve been telling you about actually runs as a virtual machine under VMware on the DC. It has 2GB of RAM, and seems to be coping fine, but with 1GB assigned to the Exchange VM, and 384mb assigned to another VM I have running on there (a web server), task manager seems to be having problems getting the memory details correct:

So we have 1GB + 384mb + whatever else is running on there (WSUS, DC, DHCP etc), and we end up with 1.0GB (or there abouts). Something’s not right. Alas, the server seems to be handling the load fine, and with a gig of RAM apparently free, I have space to expand in the future. Brilliant.