Spam Filtering For Small/Medium Business?

or_is_it writes "The company I work for has been growing dramatically and I've been charged with the task of being the gatekeeper for our GFI Spam filters. This involves manually inspecting the subject line/to/from for all caught messages in each filter rule folder. For a company of about 50 people, in one day the number of spam messages can exceed 2,000. Neglect it for a day and you end up with quite a task on your hands. I've made the rules lax enough so important messages can go through, along with a few stray spams, for which I get bitched at. Tighten the rules up and then maybe an important time-sensitive email never gets to its intended recipient, and I get bitched at. Manually reading through all those subject lines is supposed to prevent that, but I'm only human and genuine messages can easily get overlooked. How do larger organizations deal with the spam issue? I can't imagine having one centralized person manually inspecting everyone's junk-mail header is the optimal solution. Purchasing a different commercial mail filter product is a possibility, but I'd like to hear some anecdotal evidence before jumping ship."

Comments

Re:Barracuda SPAM filter

[Lershac]

Gah they are so expensive. And to keep them up to date is ridiculously expensive. I prefer free with ASSP.

Additionally I have a serious problem with the backscatter they cause. They should reject mail at SMTP time and not bounce them.

But Barracuda support is very very good. Very responsive and timely and overall a good people orgaization which can make the difference for wanting to deal with them.

Re:Barracuda SPAM filter

[Arrogant-Bastard]

There are multiple, very serious problems with Barracuda appliances. I've already commented on their propensity to generate backscatter elsewhere in this thread. They're also poorly supported, have systemic security issues, may have privacy implications (since Barracuda personnel have unauditable access to your mail stream), are expensive, use community resources such as DNSBLs in ways contrary to those resources' policies, and do not use current best practices in spam control. (This last is unsurprising given that Barracuda personnel do not participate in the discussions and consensus-building which generates those BCPs.)

Consider as well that the Barracuda appliances consist of (a) an open-source operating system (b) an open-source MTA (c) an open-source web server (d) an open-source spam scanner (e) an open-source virus scanner (f) other pieces of open-source software and (g) use community-mintained DNSBLs and RHSBLs. This is all held together with proprietary (closed-source) code, mostly for the purpose of providing a poorly-designed GUI interface. Any competent email system administrator should be able to create their own near-equivalent in an afternoon; it's not difficult. Such homebrewed creations have repeatedly been shown to vastly outperform Barracudas on multiple metrics, including cost, scalability, customization, security, and perhaps most importantly -- adaptability to new spammer techniques. (Barracuda is years behind the times and falling further back.)

It's very tempting to "just buy an appliance" and consider the problem solved, but it doesn't work. There's no substitute for expertise -- and given that much of that expertise is available for free, for the asking, on lists such as spam-l and spamtools and so on, it's difficult to understand why anyone would choose not to avail themselves of it.

Re:Client-based?

[holophrastic]

Pardon me, but I just don't see the "size". I personally (and professionally) receive well over 3'000 spam e-mails each and every day. I take about three to five minutes to run through them. For 6'000 in two days, I take four to seven minutes.

I do it without a spam filter of any kind. I have only two technique.

First, simple rule-based filters throw clients and friends into their own folders by from: line alone. That covers everyone I know in advance.

The second set of rules simply looks for my full name, my company name, my e-mail signature, my telephone number, or my mailing address. These into the "it's damn likely a legitimate e-mail" folder. This folder gets about 2 spam e-mails per week.

The remaining I simply run through, in outlook express of all clients. Sorting wins the day. The greatest trick? Sort by the to: field. It doesn't take long to see that 75 messages went to moocow@mydomain.com, 75sevens@mydomain.com, or some other horribly malformed address to that doesn't exist. Sorting by subject does similar things -- like give you "70% off . . ." which get selected and deleted in a block of one hundred at a time.

Your spam has very simple patterns to look for. Sort by them, click the first, shift-click the last, and hit delete.

Last year, I was contracted by Viagra's H.R. department to do some quick work, I made it through unscathed.