Monday, December 15, 2008
OpenDNS Problem
I am impressed with the OpenDNS service, and I use it where ever possible. I have ran into a small problem in using OpenDNS. When using it with heavy traffic applications such as Microsoft Exchange or a Microsoft SQL database you can run into connection issues. It might be intermittent connections or some cases no connection at all.
There is the theory presented on this forum. I have also suspected that the small routers are unable to handle the large amount of DNS requests quickly enough.
There are two ways to correct this problem.
1. Static IP addresses. You can set each computer on the network to a static IP address and static DNS pointing to OpenDNS. This solution works well enough for small networks. The problem can be managing IP addresses on large networks. It is not effective if you have notebook computers that travel off of the network. Be sure to pick IP addresses that will not conflict with the addresses served by your DHCP server. An example would be to start your DHCP server at x.x.x.100, and then place any static addresses below that address.
2. More robust DHCP server. Setup your server to serve DNS and assign IP addresses using DHCP. This will also alleviate the problem as well as give you a more robust and customizable DHCP server.
In a later post we will go into options for setting up a DHCP server.
There is the theory presented on this forum. I have also suspected that the small routers are unable to handle the large amount of DNS requests quickly enough.
There are two ways to correct this problem.
1. Static IP addresses. You can set each computer on the network to a static IP address and static DNS pointing to OpenDNS. This solution works well enough for small networks. The problem can be managing IP addresses on large networks. It is not effective if you have notebook computers that travel off of the network. Be sure to pick IP addresses that will not conflict with the addresses served by your DHCP server. An example would be to start your DHCP server at x.x.x.100, and then place any static addresses below that address.
2. More robust DHCP server. Setup your server to serve DNS and assign IP addresses using DHCP. This will also alleviate the problem as well as give you a more robust and customizable DHCP server.
In a later post we will go into options for setting up a DHCP server.
Sunday, June 29, 2008
Low-Cost Internet Content Filtering
If you manage a small network at the office or even your home you want to protect employee's productivity and your child's nativity. There are many solutions that you can purchase from centralized appliances to software that installed on individual computers.
OpenDNS offers a free, easy-to-use solution. I have used OpenDNS at several locations for quick domain resolution for a couple of years. The advantages of OpenDNS over your ISP DNS servers is that on many occasions the DNS machine at your ISP is most likely a long-forgotten, over-worked box in the corner of the data center. This can slow your web surfing.
In addition to speed, OpenDNS can now also provide content filtering for your network. You go to the OpenDNS.org web site and register for an account. You can then setup your network and filtering options on the site. In addition to filtering, OpenDNS will also track web sites accessed from your network.
Once you have setup your network(s) on the web site you will need to make some changes to your network. The easiest place to make the change is in your DHCP server which will be in your router on small networks. Enter the DNS servers given to you by OpenDNS.
If you have a dynamic IP address, OpenDNS provides a small utility that you can install on a Windows or Mac computer so that OpenDNS can keep track of your changing IP address.
Understand that this is not bullet-proof fix for content-securing your network. A knowledge computer user will know a work-around if they are really intent on finding questionable content on the Internet.
OpenDNS offers a free, easy-to-use solution. I have used OpenDNS at several locations for quick domain resolution for a couple of years. The advantages of OpenDNS over your ISP DNS servers is that on many occasions the DNS machine at your ISP is most likely a long-forgotten, over-worked box in the corner of the data center. This can slow your web surfing.
In addition to speed, OpenDNS can now also provide content filtering for your network. You go to the OpenDNS.org web site and register for an account. You can then setup your network and filtering options on the site. In addition to filtering, OpenDNS will also track web sites accessed from your network.
Once you have setup your network(s) on the web site you will need to make some changes to your network. The easiest place to make the change is in your DHCP server which will be in your router on small networks. Enter the DNS servers given to you by OpenDNS.
If you have a dynamic IP address, OpenDNS provides a small utility that you can install on a Windows or Mac computer so that OpenDNS can keep track of your changing IP address.
Understand that this is not bullet-proof fix for content-securing your network. A knowledge computer user will know a work-around if they are really intent on finding questionable content on the Internet.
Labels: content filtering, network, OpenDNS
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