From the category archives:

Transport

Using Transport Rules to protect your organization from the ‘Here You Have’ Worm

September 10, 2010

The Here You Have worm, also known as Visal.B, has been spreading through network shares and email (more details on Microsoft’s Malware Protection Center web site). When spreading through email, the worm sends itself to your contacts with the following strings in the Subject field and message body: Subject: Here you have Body: Hello: This [...]

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Removing internal host names and IP addresses from message headers

May 20, 2008

Another frequently asked question about SMTP mail – how can I remove internal host names and IP addresses from outbound Internet mail? More often than not, this results from the belief that somehow if the outside world finds out an organization’s internal IP addresses and host names, it makes the organization vulnerable. Auditors love to [...]

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HOW TO: Prevent a user from sending and receiving internet mail

July 10, 2007

Many organizations want to restrict certain sets of users from sendig or receiving Internet mail. “How do you prevent a user from sending or receiving Internet mail?” is a frequently asked question. Here’s how to accomplish this in Exchange 2010/2007 and Exchange 2003. Restricting outbound internet mail for some users On Exchange Server 2003/2000, this [...]

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Logging SMTP Protocol Activity in Exchange 2010 and Exchange 2007

May 3, 2007

I wrote about SMTP logging in Exchange Server 2003/2000 in what is one of the most popular posts on Exchangepedia [read previous post - "Logging SMTP protocol activity"]. Exchange Server 2007 has its own SMTP stack, and what I like to think of as smarter or more intelligent Receive Connectors (these are protocol listeners, roughly [...]

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Protect users from spam from your own domain in Exchange 2010 and Exchange 2007

May 1, 2007

One of the common complaints from users and many messaging folks is spam received from senders that appear to be from your own domain. SMTP mail is exchanged with anonymous Internet hosts without any authentication. Headers can be and are effortlessly spoofed. Rather than using an unregistered or invalid domain in the From: header, many [...]

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Exchange Server 2007: How to turn off the Back Pressure feature on transport servers

March 29, 2007

In reference to previous post titled “Exchange Server 2007 Transport: 452 4.3.1 Insufficient system resources“, the Back Pressure feature, that detects resource pressure on Exchange Server 2007 transport servers and stops accepting new message submission if low on resources, can be turned off. Here’s how to do it: Open the EdgeTransport.exe.config file from \Exchange Server\bin [...]

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A Late New Year’s Resolution: Do Not Resolve Anonymous Senders

January 19, 2007

It’s probably a little late to make another New Year’s resolution, but I’ll try to convince you to make one nevertheless. By default, when an internal/authenticated user sends you a message, you see the user’s display name (for example Joe Adams) in Outlook/OWA and other email clients. Messages from unauthenticated senders, including those from Internet [...]

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Enabled by default: SMTP Tarpit in Exchange Server 2007

January 9, 2007

From a recent discussion, and something I’ve been wanting to post about for a while: SMTP tarpitting is enabled by default on Receive Connectors in Exchange 2007 (and Exchange 210). What is SMTP tarpitting? It’s the process of introducing a delay in SMTP connections from hosts that are suspected of inappropriate SMTP behavior – for [...]

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How To Allow Relaying in Exchange 2010 and Exchange 2007

January 3, 2007

In Exchange Server 2003, you can allow anonymous SMTP hosts to relay mail by adding their IP address(es) in SMTP Virtual Server Properties | Access tab | Relay. Hosts that require anonymous relay capability include application servers and devices such as copiers, which scan documents and send them as email attachments. Figure 1: Controlling relay [...]

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