Ask the Expert

Problem receiving internal email

I am doing some work for a relative who owns a small company. They are using Windows 2000 Small Business Server (SBS) on one server platform and host six clients locally. The clients are going through the (proxy) server for Internet and email access. They are using Exchange for local email and also use an ISP for Internet mail. I recently added a laptop but have not been able to successfully send email from the office (behind the server), though I can receive outside email without any problems. The server is running ISA Server as a firewall add-on; I disabled this at one point and nothing changed. What is wrong?

    Requires Free Membership to View


This is an ISA configuration issue. You need to make sure that ISA is configured to allow port 25 (SMTP) from the internal network (Small Business Server included) to the Internet. ISA can be tricky to configure, and when it is integrated on the same server as the applications it is trying to protect, you are talking even more complexity. I would suggest, as a best practice, you use a separate server to set up ISA or simply use an inexpensive firewall device instead. I think you will have better luck.


With Windows Small Business Server (SBS) 2000/2003, you also need to be a member of the BackOffice Internet Users security group or ISA Server won't let you browse the Internet or send email out. If the other systems are not having problems with email or browsing, only the laptop, then ISA Server is not going to be blocking port 25 outbound.
—Alan C.

Do you have comments on this Ask the Expert Q&A? Let us know.

Related information from

  • Article: Should you use ISA Server as your Exchange firewall?
  • Step-by-Step Guide: How to use ISA Server as an SMTP filter
  • Expert Advice: Firewall recommendations and VPN support
  • Reference Center: Exchange and ISA Server resources
  • This was first published in February 2005

    There are Comments. Add yours.

    TIP: Want to include a code block in your comment? Use <pre> or <code> tags around the desired text. Ex: <code>insert code</code>

    REGISTER or login:

    Forgot Password?
    By submitting you agree to receive email from TechTarget and its partners. If you reside outside of the United States, you consent to having your personal data transferred to and processed in the United States. Privacy
    Sort by: OldestNewest

    Forgot Password?

    No problem! Submit your e-mail address below. We'll send you an email containing your password.

    Your password has been sent to: