Inexpensive, effective mixed-platform Network Security using Linux-based solutions. 

Horizon Network Security™
phone: +1 770-662-8321, email:

Our Enterprise-level Spam and Virus Filter blocks 98.5% of spam, requires no training or user maintenance, and is very affordable at only $1495 plus $99/mo.

Linux Spam Filter, Antivirus Software

We have created our own Enterprise-grade Spam and Virus Filter that outperforms the "big-name" competition and at a much better price of only $1495 plus $99/mo. It blocks 98.5% of spam, offers White and Black lists and we do the installation and configuration. You just have to say "I don't want any more spam or user complaints about it!"

Spam Filter

90% of most received email is spam! Our spam filter typically filters out 98.5% of this spam so your people will not waste their valuable time reading it, get frustrated, or, worse, accidentally delete legitimate email as spam or be tricked by fraudulent email or viruses. Unlike some of our competition, you do not have to "train" our filter. It already knows what to filter out.

The Spam Filter blocks or flags most spam by context filtering (matching spammer phrases such as "get rich quick"), by known bad source IP addresses, by Sender Policy Framework (SPF), by checking Domain Signatures provided by Yahoo to reject false claims that the sender is a Yahoo address, by many other similar "spoofing checks", especially rejecting external email claiming to be from your domain and trusted associates, and by known bad URLs in the message text.

The context filter recognizes common words and phrases that appear in most spam Subjects, From, and To addresses, as well as the body and elsewhere in the headers and envelope. Our context filter is one of the most sophisticated in the business and contains many thousands of variations on common "come-ons", including misspellings.

The source IP address filter uses a very large, frequently updated database of IP addresses from known spammers, ISPs and organizations that allow their users to send spam, "open mail relays" that are misconfigured to allow spammers to relay spam mail through them, and dial-up and residential IP addresses that clearly have no administrative restriction.

Sender Policy Framework (SPF) is a brilliant free Open Source invention that eliminates spoofed mail. All a domain needs to do is add some DNS (Domain Name Service) records indicating the IP addresses of the mail servers it uses to send email out to the Internet.

When we receive email claiming to be from,,, or we simply use SPF to ask the real domain's DNS server if the sending mail server's IP is one of the official mail servers of that domain. If it is not then the email did not really come from that domain -- it was spoofed -- and we block it. There is no way for a spammer to evade it.

Join AOL, eBay, Hotmail, the smarter banks in the U.S., Switzerland, and elsewhere and others in putting SPF to work for you with SPAM Cracker™. We also can help you set up your own SPF DNS records so spammers cannot claim to send from your domain (to others using SPF).

It does the lookup for known spammer sending IP addresses as soon as the spammer connects to your system. It can reject the email before the spammer even has a chance to waste your bandwidth with kilobytes of spam. The SPAM Cracker can even add a rule to the firewall so the spammer can't ever connect to you again, thus saving valuable bandwidth.

You can control which domains to filter for spam/viruses (Great for web hosting companies). The filter can be set to flag the spam on the Subject line and deliver it rather than block it entirely. Its many features are very configurable to meet your needs rather than a "one size fits all" mentality.

Tired of getting spam from Korea, Russia, China, Brazil, Ukraine, or Romania? We can block those top-level domains or all top-level domains except for the ones you correspond with.

Tired of spam in a foreign language? We can block that too.

Our Spam filter can also be configured to work with No Guess Domains™. On these domains, a list of valid recipients (mailboxes) is specified. If any message includes at least X invalid recipients the message is flagged as spam. This handles spammers who will guess mailbox names and then send hundreds or thousands of emails to those users at a given domain. X can be set to >1 to allow for a mistyped address. Our Spam filter also works seamlessly with our Cracker Trap™ firewall. If the number of invalid recipients on a piece of email exceeds a preset number, the sending IP is added to the firewall's blocked list so they will not trouble you again.

The virus filter blocks known viruses by recognizing their binary signatures. Don't be fooled by cheap Virus filters that just check for the easily changed text message that accompanies the real Virus. Ours uses a frequently updated virus signature database delivered to your system in a secure manner four times a day automatically.

It also filters out dangerous extensions, such as .com and .exe, thus preventing most new viruses from infecting you even before they get into the world's master virus signature databases. Thus, you are protected even the instant a new virus is unleashed. Don't suffer with our competition, risking getting infected before they discover the new virus and add it to their virus database.

The Spam and Virus filter may be installed either on your Linux-based Firewall or on your Linux Mail server or on a separate system that we can supply. If installed on your Firewall or separate system it will work regardless of whether your mail server runs on Linux, Unix, Windows, Mac, VMS, or any other platform. The Firewall option requires no reconfiguration of any part of your network, including your upstream routers or your mail servers. It is ideal for small firms to large organizations where distributed responsibility and mixed platform multiple mail servers would make other options inconvenient or impossible.

Its price is quite competitive and its abilities are second to none. Because it runs on a very hardened Linux system, it is unlikely to be compromised. Most Windows Viruses, as the first thing they do, immediately will disable a Windows system's Virus filter and Firewall. This would render your network vulnerable not just to that virus but to any virus or port-based attack.


Contact us at or +1 770-662-8321 contact us to learn more and stop spam now.