Windows Forum

Ask something
Discussion Locked

Restricting outbound DNS access on Win98

0 helpful
5 replies

by flyinbyfaith

Closed to new repliesThis discussion is closed. It stays readable, but it takes no new replies.

Background: Email server being hosted by external company on public IP address. We have no internal DNS server, but use our ISP's public DNS servers ip addresses.

Problem: I have a couple of PC's that need access to the Email server using Outlook/Outlook Express, but I don't want them to have full access to the internet. Ideally, I would like to have a simple solution, such as including the ip address for the mail server in the hosts file restricting them to only access that public ip address. Currently they have the DNS server addresses in their tcp/ip networking properties, and they have full access.

Is there a way to effectivly restrict these computers to a single public ip resolution, so that they can retrieve email only?

5 replies

by timwalsh

Give this a try:
In the server settings of their email profiles, instead of entering the URL (mail.ISPdomain.com), enter in the IP address for server (or servers). By doing this, no DNS resolution needs to take place. You can then remove the DNS server entries from their TCP/IP properties.

by flyinbyfaith

Thanks for helping me recover from overlooking the simple solution. Using the IP address instead of the mail server's name worked exactly as desired. I would still like to know how to actually use the host file, so that I could use that to create a "limited access" option when the need comes up. If you have any good references or links on using the hosts file that would much appreciated.

by vh_s

Answer 1 is correct.

Put the ip address of your POP / SMTP server directly in the required box. Since it is an ip address, no resolution need to take place. Therefore you could remove the DNS entries in the network properties. For advanced users, this trick won't work though, since they would replace it back with the old value ( settings ).

Or,
Put a proxy server in place.

Since you have an external email server, your network must have a kind of router to redirect external request to the ISP. Place a proxy server just before the router, therefore applying filter to internal->external communication.

A bit of work, true, but then you can configure much more than this. Since you are a kind of network administrator that need control, I would suggest to set it in place :)

vh_s

This discussion is closed to new replies.