Inter7's Newsletter: Spring 07 Technology Update Inter7 is proud to announce the latest updates to our product and service offerings. We continue to improve our open source solutions for the ever changing and demanding needs of email and telephone users.

New Software Versions Listed Below Help Reduce Spam

The graph on the right shows the change in the amount of email messages accepted by qmail on a production server after installing the new software versions listed below. The left side of the graph is after the installation at 16:00 hours (4pm) and the right is before the installation. As you can see there was a significant reduction in emails accepted by the server. All of the reduction was due to rejecting spam emails. All valid emails to and from customers continued to be accepted. We highly recommend updating your qmail installation to help reduce spam email and lower the processing load on your server.

New ClamAV Virus Version 0.90.1 Released

The Clam AntiVirus development group has released another version of the engine that blocks more virus types. It uses a little more CPU time but we have optimized the configuration options to help minimize the increased load. As with all of our new offerings this version of ClamAV has been rigorously tested in high volume production environments.

Windows Grey Listing to Help Block Spam

In the last four or five months we have seen a significant increase in spam coming from infected windows machines that are controlled remotely by spammer networks and commanded to send out email for them. Windows grey listing blocks almost all of these emails.

How it works:
When a non customer attempts to send email to the machine, we inspect the network packets to identify the senders operating system. If it is a windows machine we record the To and From email addresses and the IP of the sender. If this is the first time they have connected we return a "please try your email again later" message. All valid email servers will attempt to send the email again so no messages are lost. After about a minute when they send the email again the system accepts the email and automatically white lists the sending server. Windows grey listing ends up blocking spam because infected windows machines do not bother sending the email again or they try again immediately. Valid windows email servers like Microsoft Exchange, yahoo.com or hotmail.com all try again. So their email is accepted with delay of only about a minute and the spam is not accepted.

Qmail Update for Real time Black hole List (RBL)

One of the best ways we block spam is by checking a senders IP address against well respected Real time Black Hole lists. These lists keep track of the IP addresses of reported spammers. One of the best sites, spamhaus, now includes IP addresses of end users since so many end user run Microsoft Windows and are infected with spam viruses. This Qmail update now skips the RBL checks for your authorized users. So your server can stay up-to-date with the latest Real time Black hole lists and still allow your users access to email services even if those IPs are listed in an RBL. This helps reduce support calls.

SpamAssassin update version 3.1.8 with rules de jour

SpamAssasssin has a new release version 3.1.8 that fixes a possible denial of service when processing overly long URLs found in malformed HTML emails. Processing of these messages can take a very long time an consume large amounts of memory. The possible denial of service occurs when memory is exhausted and swap thrashing starts. Version 3.1.8 fixes the problem. We also install a selected set of rules de jour from the spamassassin rules emporium with automated weekly updates of rules.

DSpam alternative to SpamAssassin

DSpam is a very efficient replacement for spamassassin that empowers your users to decide what is and is not spam. Users can tell the email server, by forwarding the message to an email address or moving the email into a Junk folder. DSpam then uses several mathematical methods to learn what is spam. As time goes by and spammers change the format of their emails or start trying to sell new products DSpam learns and automatically creates new rules. So DSpam essentially never needs an update like SpamAssassin does. When users see a valid email that is marked as spam they can forward the email to the system and DSpam will white list the sender. So there is no need for System Administers to manage white listing. To protect the learning process only your authorized users can train DSpam. We at inter7 have been using DSpam for about three months with great success and highly recommend it.

Asterisk Phone Server Update with New Web Interface

The Asterisk open source group has released a new version 1.4.1 that includes a very nice user interface for managing the Asterisk configuration. This update also includes complete re-writes of parts of the system and much more flexibility in configuration. The new web interface is very well looks very professional.

Citadel Server

Inter7 announces our new Citadel server that provides Virus and Spam blocking for less secure email systems like Microsoft Exchange. We use our standard open source configurations to provide a lower cost and no license fee replacement for products like the Barracuda Spam Firewall. It can also be configured to run at a remote site with better Internet bandwidth to help reduce the network usage on slower speed Internet connections at an office.