Cannot browse Internet through ISA Server
I am having problems with name resolution on my computer that runs Internet Security and Acceleration (ISA) Server. Each time I attempt to connect to the Internet, I receive the following error: Cannot find server or DNS Error Internet Explorer. However, I am able to send and receive e-mail on the computer running ISA, and all ISA clients can connect to the Internet with IE. I have done the following:
- I have configured my Web browser on the computer running ISA Server as a Web Proxy client, with the IP address of the internal interface and the correct port number.
- I have also configured the internal interface of the computer running ISA, with the internal IP address of my DNS server.
- On the external interface of the computer running ISA Server, I have configured the IP addresses of my ISP DNS servers.
- I have double-checked all IP addresses and port number, and they are correct.
Also, from the computer running ISA, I am able to ping my internal DNS server and my ISP DNS servers.
Why am I still unable to connect to the Internet via Internet Explorer on the computer running ISA? Thank you for your assistance.
It's great to see that you have taken the time to research this issue and document your configuration here. You do not mention what you have done with the IE settings. Have you tried setting the connection information (Tools -> Internet Options -> Connections -> LAN Settings) to point to the ISA Server's internal IP address and port 8080? This has to be done. From here, you can browse the Internet from ISA Server. (Though I question whether this is a good idea -- it's an additional risk; as is your use of the ISA Server to send and receive e-mail. In fact it's not a good idea to do anything non-firewall related on any firewall.)
This was first published in February 2003