CAEN

On Monday, April 20, 2009, in response to a DNS (Domain Name Service) server attack we restricted a feature on the College of Engineering (CoE) DNS servers, called recursion, from off-campus networks. Recursion refers to the process of having a DNS server make queries to other DNS servers on behalf of a client who makes the original DNS request. Prior to April 20, the DNS servers looked up the name and IP address for any host, both internal and external, from a non-University IP address. After the recursion change, only requests for name and IP information to hosts internal to the CoE network will work from non-University IP addresses. Lookups from University IP addresses to anywhere on the Internet will continue to work. For security purposes, this change was already planned for early June, but the attack moved up our timeline. This means that if your machine is connected outside of the University network, you will not be able to use the CoE DNS servers for lookups. The CoE DNS servers have IP addresses of 141.212.2.69 and 141.212.2.81.

Internet Service Providers, such as Comcast and AT&T, provide their own DNS servers. If you have your computer set up to obtain an IP address automatically, you should set up your computer to obtain its DNS servers automatically, and it should begin using the DNS server of your ISP. Your departmental computer support staff will be able to assist you with changing these settings.

Configuring Windows Vista

1. From the Start menu, choose Control Panel.
2. Open the Network and Sharing Center.
3. Under the left Tasks menu, select Manage network connections.
4. In the resulting window, right-click your network connection and select Properties.
5. Under the Networking tab, highlight each Internet Protocol Version 4 (TCP/IPv4) & Internet Protocol Version 6 (TCP/IPv6). Click the Properties button for each:

4. Select Obtain DNS server address automatically.
5. Click OK to close the properties window.

Configuring Mac OS X

1. From the Apple menu, select System Preferences...
2. Under Internet & Network, click Network.
3. Select Ethernet from the left menu, and click the Advanced... button.
4. Click the TCP/IP tab, and you will see a window similar to the following:

4. Select Using DHCP from the Configure IPv4 drop-down menu.
5. Select Automatically from the Configure IPv6 drop-down menu.
6. Click OK to close the network window.