Blog Archives

Experts Exchange t-shirt

I wore my Experts Exchange Master t-shirt to the parade in Temple Terrace yesterday, but there must not have been many IT people there, I didn’t get any comments or looks. Which I guess could be a good thing. Now if I had worn that shirt to a computer show, I’m sure I’d have gotten some comments. 😉

Experts Exchange update

Sadly, my account with Experts Exchange has been downgraded to a free account 😦 I’ve been busy lately and took a vacation and did not maintain enough expert points each month so I am now only a free member. I have to answer a few questions to get my membership restored, which won’t be a big deal, but still a pain. Whats funny is the same day my account was downgraded, I received my Experts Exchange t-shirt. The shirt was free to commorate my achievements at EE as a Master level Exchange expert.

Issue with Public LAN in Windows – Exchange Clustering

Yesterday I began a demo of a Windows Server 2003 Cluster running an Exchange 2003 virtual server. This is a 2 node active/passive cluster. Everything was fine until I got to the part where I was showing hardware failure and the resulting failover performance. I unplugged the public LAN ethernet cable from the active cluster node. To my dismay and embarrasment the cluster administrator locked up and failover never happened. I was sure I had tested this particular scenario before during the initial setup. After thinking about this a little more I probably tested this with the default cluster during setup, and not after Exchange was up and running. Why would you want to disconnect the public LAN cable right? Well, when tested I discovered that Exchange in a cluster is very sensitive (as it usually is) to losing its public LAN interface. Anytime Exchange (clustered or not) loses connection to AD and DNS, it can hang. Well my problem was cuased by the Exchange 2003 services hanging once public LAN connectivity was lost. I found that the cluster was trying to stop the Exchange services but they were hanging. The cluster can’t failover to the second node until the core Exchange services are stopped and Exchange cluster resources are marked as offline. So because the services were hanging, my cluster would not fail over to the second node.

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When NT4 servers can't find the PDC and all else fails

Recently I ran into a major problem with my Active Directory and NT4 setup. I maintain a network made up of 2 NT4 BDCs and about 10 Active Directory Domain Controllers. The domain is in 2003 interim mode and we also run Exchange 5.5 on 4 other NT4 member servers. Last week we renamed a few domain controllers and assigned new IP addresses (on the 2003 side). As a precaution I kept the old IP address on one of the major domain controllers until I could get time to manually modify all the legacy servers lmhosts files. We also shutdown the domain controller that was used to get us to Active Directory, basically I took a dell desktop that would run NT, and made it a BDC. Then I promoted it to a PDC and upgraded the OS to Server 2003 and installed Active Directory. Well its time to de-commission that box and we shut it down last week as well. On Monday, I created a new user account and immediately got reports of strange problems, the user was getting prompted for logon credentials in Outlook and could not stay online.

I looked around and couldn’t find anything wrong and wasn’t too concerned at this point. Later I realized that my NT4 BDCs were not able to find a PDC any longer. I assumed it was because we shutdown the upgraded domain controller and so we powered it back on hoping it would help. This did not fix the problem so I began working on the issue by online research and posting questions in newsgroups. Finally I found a guy on Experts-exchange that was very helpful and worked with me on EE for hours before we figured out the issue. By troubleshooting and much testing we found that NetBIOS lookups to the PDC emulator (running 2003) were failing. From 2003 we could map drives, browse to NT4 without a problem, only from NT4 to 2003 was there an issue. Lastly we found that its bad to have a multi-homed domain controller, especially the one we were using for the PDC Emulator. I removed the second (old) IP address from the server and everything started to work just fine. I could get into the user manager in NT4 and updates started to be processed without a problem.

So it turns out the main cause of the issue was not the renames, or IP change, or even shutting down an old DC. It was simply that we had more than 1 IP Address on our PDC Emulator server. Removing that fixed the issue. I think we can now power down the upgraded DC again and proceed further with the migration. Too bad it took so long to figure this out, but at least it is working normally now.

Experts-Exchange Master Level Certification in Exchange Server

Experts Exchange

Since joining Experts-exchange.com a few months back, I’ve been working towards getting at least one expert certification. I am pleased to announce that I have finally obtained my first expert certification. I now have a master level expert certification in Exchange Server. Thats the topic I am in most of the time and have helped many people over the last few months. It only takes a small amount of time to answer questions and point people in the right direction. I love this site, because not only can I ask questions and get help from experts even more “seasoned” than myself, but I can help others at or below my level deal with issues in which I have experience. I now have 134322 expert points and have finally earned over 50,000 points in the exchange category, which earned me my certification. I plan to continue to participate in Experts Exchange and expand my certification status.
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Home Network – Part 3

Microsoft Active Directory:
My home network is built on Microsoft’s Active Directory. I use active directory to organize my user accounts (all two of them), my computer and group policies. With group policies I can set common variables for all my workstations, servers, etc. This way I don’t have to hand configure everything, its all automatic. Group Policies are a great way to manage your network workstations or servers. There are other solutions here, some people like to run Linux at home, and I’ll admit, I do too from time to time. I love linux, but there are still too many apps I use that require Windows. From time to time I demo some of the latest Linux distributions and try things out. I think its great, and if I had a 4th computer to run it on, I’d probably run a linux server or desktop as well. Some people like novell, some people like MAC, its up to you. This is just how I am doing thing. I have group policies set to add customization to my desktop mainly. Things like a browser title, automatic update settings, common software distribution, etc.

Domains, e-mail and more:
I guess I can’t go much further without explaining how I also do my domain names and websites. I’ll write more about this topic later on as a how to and what you should know for getting your own domain and website. But for now, I’ll keep it simple. I own several domain names which I use for various purposes. I have one domain that is for all my server equipment, like my hosting server that hosts my website and some other websites I host for people (for free unfortunately). These servers are in a data center and I simply “rent” the server from them on a month to month basis because its cheap and does what I want it to do. Plus they take care of maintenance and problems. Then I have a primary domain name I used to use for my hosting company’s website. The backend server domain ended with a .net and the primary domain is a .com. These extensions can be anything you like, but I stuck with a traditional format. Then I have a third domain for my personal website which is mainly for my family and my blog, etc. Here is where the bulk of my incoming and ougoing e-mail comes from, the other two domains are mainly for servers and a now closed hosting company. I do have some other domains, but don’t really used them yet. I’ll be expanding that later on as well.

E-mail:
So now you know I have a shared hosting server which hosts my websites and most functions of my domain names. Now when it comes to e-mail, you’d naturally assume this server also handled mail for my domains as well right? If you said yes, you’d be wrong. I’m using a service called Rollernet which is a mail forwarding service. Since my ISP restricts incoming traffic on port 25, it was necessary to setup SMTP on a non-custom port. However, this causes a problem because when someone on the internet sends me an e-mail, most mail servers only send mail on port 25. So if I’m running SMTP on a non-custom port, how do I get my mail? Here is how. Rollernet’s servers are listed as the MX records for my domains. This means, that when you send me an e-mail, its actually received on port 25 by rollernet. They take the mail, queue it, do some scans on it for viruses, spam etc, then they forward that mail to my home mail server on a custom SMTP port. Of course I have this port setup in my cable modem and firewall to allow it to be forwarded to my mail server which resided on my LAN. Now here is the complicated part. My home mail server received mail on a custom SMTP port and is received by NoSpamToday, which is my SMTP level SPAM filter. NoSpamToday (NST for short), filters for SPAM, viruses etc, and basically makes sure that the message is valid before it allows it in to my mailbox. Now NST is not a mail server, its just a SMTP server, so another component is needed here, thats where 602 Lan Suite (LS for short) comes in. NST received a message for me on a custom SMTP port. Once it makes sure that the message is valid, it then forwards that message to 602LS which receives the message on the standard SMTP Port 25. 602LS receives the message and performes a few checks of its own, like scanning it again for viruses, doing aother SPAM check and finally delivering it to my mailbox. 602LS also has a built in webmail server, so I can check my webmail from anywhere in the world. This is also where port forwarding comes in as the ports for webmail need to be setup to route to my home mail server from the outsite. Using my public DNS zone, I can add a record for webmail to my domain, so I can go to http://webamil.mydomain.com/mail and get to my web interface. This way I don’t have to use DynDNS or any of those services, since my public IP on my cable modem rarely changes. Now if it were to change, I’d have to manually update that in my DNS zone. So watch out for that if your using this scenario. I am aware of it and know what to do, so for me its not a big deal, but if your new to this, don’t set this up and wonder why it breaks 9 months later. Keep an eye on your public IP.

Lets now talk about outgoing mail. I don’t know if your like me, but I find myself in situations at work and abroad where I find that my company network or hotel network restricts SMTP servers to their own servers and won’t let you send mail using your own SMTP configuration. For example, at work I run a simple server monitor that sends alerts. But my company has a firewall in place that limits outgoing SMTP traffic on port 25. Now I bet your wondering where the SMTP component from IIS comes in to the picture from my previous post. Here it is. I am running IIS on my mail server but only the SMPT component. So I setup Microsoft’s SMTP service to listen on a custom port (different from my incoming SMTP port for normal e-mail from Rollernet). This way, I can setup my monitoring server to use my custom SMTP server at home to send the alerts. So in my situation, my monitor program detects a problem with a server in my office, it sends an alert to my home mail server on a custom SMTP port. My SMTP server then relays that message to my shared hosting server which then sends it to the desired recipient on a standard SMTP port. This way, I can use SMTP wherever I am, still get my messages or alerts sent and accomplish my tasks. This custom SMTP service is protected by a username and password and relaying with it is denied. Relaying on NST is also forbidden. Ok, so how about my home PC? Ok, simple, we use outlook on our home PC, so outlook is setup to send/receive mail from 602LS through POP3 and standard SMTP. We send a message from outlook, it is received by my home mail server on port 25, which then forwards that mail to my shared hosting server. Some ISPs also restrict outgoing SMTP traffic, so here you may need to setup a custom port on your public SMTP server and configure your mail server to send all outgoing mail over a “SmartHost” or custom SMTP configuration. My shared hosting server then delivers the mail over standard SMTP to the recipient’s mail server.

So in summary, yes this is a complicated setup, and no it may not be for everyone. But I will say this, there is a degree of pride that goes into setting soemthing like this up. Now I’m a Microsoft Engineer, so I’ve been doing networking for a long time. No this is not the way to go about setting up a business or large company. Obviously I’d recommend using Exchange or more powerful mail servers and betters ISP connections. But if your a techie and want to setup a really cool home network, this guide might just help point you in the right direction.

Other Services:
Lets talk remote access. So how do I manage this home network when I’m not home. Easy, RDP. There are lots of people around that don’t like RDP, its not very secure, and has its issues like any other software or technology. For me however, its perfect. I simply forward port 3389 from my cable modem to my firewall and from my firewall to my PC, I can remotely manage any machine on my home network. Now I took it a step further, and actually setup a custom RDP port on my other machines, like my servers and second desktop. This has the advantage of being easy to individually RDP into any machine on my home network without first having to remote into my home pc and then into another machine. In conjunction with DNS for easy naming, its a snap. All you need to remember is the custom port number for each machine. I only have a few so its no big deal, if you have many machines I’d recommend finding a better way, such as VPN. Through RDP I can remote control, and virtually manage any server or desktop on my home network.

Web management: I also use a program called Remotely Anywhere (www.remotelyanywhere.com). Its a great application that runs as a service on Windows. With it, you can remote control, Transfer files, totally manage all aspects of the machine right from a web browser. Its very robust and powerful, with tons of additional features too numberous to mention. Its one of the best web based remote control/management solutions I know of. This can also be setup on a custom port, so it will need port forwarding configured for it as well.

FTP: I used to have a NAS server with FTP setup so I could FTP directly to my RAID5 storage device. Now that its gone, I don’t really use FTP anymore so I removed it. I use an FTP site on my shared hosting server temporarily if I ever need to send anything through FTP. I can grab it from home later.

Internet Access: Because my cable modem and firewall do NAT, its very easy to provide for internet access to my workstations and servers on my home network. The firewall is the gateway on my network, and Microsof’t DNS handles all DNS related operations on my network. My DNS server is configured to forward all requests for external host names to my ISP’s DNS server. It then caches the results and can reply much faster to any requests my workstations or servers make. Internet access is basically a simple NAT solution provided by my firewall and cable modem.

Points of Failure:
With a system like this there are other considerations that need to be taken into account. Amoung them are power, redundancy, damage, replacement, etc. For example, if my power goes out what happens. Well for me I have my critical equipment on a UPS. Since this is a home network and not a critical system, the UPS will keep my servers and internet connection up and running for 5 minutes. This should be sufficient as long as the power isn’t out for long, which is isn’t usually. What if my firewall or cable modem goes bad. Well then I have a problem, as with my ISP I have to have them come and activate a new cable modem. So I’d first have to buy a replacement and then have them install it. This can be done usually by the next day. So what if my mail server or other network equipment is damaged. Well, for mail, if my home mail server becomes unavailable, mail will queue at rollernet, so I won’t loose any e-mail. I can even redirect that mail to my shared hosting server if I wanted to so I could get to it. If some of my network gear fails, it will obviously need to be replaced. I’d try to repalce it with exactly the same modem so that if it had a configuration with it, I could easily restore a backup config file to immediately get my network back up and running.

Security: What about security, how secure is this setup? Very secure. Even considering I have ports forwarded into my LAN from the outside. This often makes security experts very nervous and for good reason, but again, this is not the NSA, I don’t have anything on my home network worth anything to anyone but me. That is not an excuse for having bad security. First, I have a double NAT solution, so even if someone could hack in past my cable modem, they couldn’t get further than my firewall. If they could get past my firewall by some miracle, they would not be able to access anything on my network, since all network traffic between workstations and server is encrypted through Kerberos. The worst they could do if map out my network and find my IP addresses. DOS attacks are also a possability, but there isn’t much that can be done about that anyway. Again, I’m not saying good security isn’t important, and the measures I’ve taken are sufficient for my needs. Please don’t think I’m advocating bad security measures.

Thanks for taking time to read this post, I know it was long. Keep an eye out for more tech posts in the near future. I’ll also post some images giving you a visual of how all this works. Here is a simple visual aid of what I’m talking about above.]]>

Experts-Exchange

For a few years now I’ve been seeing a website called experts-exchange.com. Usually I see this site come up in google searches I perform for tech issues. I’ve always wanted to get a membership to this site, but didn’t want to pay for it. Well, last week I ran into some tech issues and I happen to run across this site again. I finally decided to sign up for their basic membership. I didn’t buy any points, I switched to expert mode and started to answer a few questions for people. To my surprise people started rewarding me with large point rewards. I’ve gotten 3000 from one guy, 1500 from several others and or course many smaller point rewards. I’ve been a member now for one week and one day. I now have almost 22 thousand points!!! Once I reached 10 thousand points I was able to upgrade my membership for free to the premium membership level. I was able to reach the 10 thousand point level in just 2-3 days. I now need to maintain a point income of 3000 points per month to maintain my premium membership level.

This site is great because I can now ask unlimited questions with unlimited points (question asking points). I’ve only asked two or three questions, but the availability is great, because I can get my questions answered as well as help other people get their questions answered as well. Its like a big tech community. Experts are there to help people with technical issues, and techs can also ask questions if they run into something hard.

Check out http://www.experts-exchange and look for me, MCPJoe

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