I am interested in what folks are using for perimeter SPAM filtering services.

The service must:

  • plug in via MX records in DNS (e.g. MX -> perimeter filter -> my mail server)
  • can be secured such that only the perimeter service can connect to my mail server
  • can be free or paid
  • provide a control panel where I can manage my users, alias entries, etc.
  • must include filter tweaking (e.g. it must not be up to me to tweak filters)
  • user-accessible quarantine

Further Clarification:

  • I am not interested in any appliances or firewalls where I have to maintain hardware/software on-site.

PS: Thanks to all who are contributing, I am upvoting answers that provide:

  • Clear description of the service
  • Tell about their personal experience or evaluation of the service
  • Update from arrocharGeek 2010-09-08: We are using cudamail.com - they provided hosted/managed Barracuda Networks SPAM filtering. They provide all the features I listed above at a price suitable to my company's budget. We are super happy customers now for over 1 year. DISCLAIMER: I have not relationship to cudamail.com other than happy customer. I highly recommend it. Simpler than Postini, almost no management required at all.
    – qxotk
    Sep 9, 2010 at 2:17

9 Answers 9


Postini (aka Google) - pretty inexpensive, not that intuitive to administer but its not too bad.

  • Postini rocks the house!
    – p.campbell
    May 4, 2009 at 2:44
  • Lately though Postini has been missing a lot of spam - at least for me. It did rock the house when I first got it a year or so ago, though!
    – Keithius
    May 4, 2009 at 14:35

Microsoft Exchange Hosted Services (aka Frontbridge)

Microsoft Exchange Hosted Services (EHS) offers online tools to help your organization protect itself from spam and malware, satisfy retention requirements for e-discovery and compliance, encrypt data to preserve confidentiality, and maintain access to e-mail during and after emergency situations.

  • We started using Frontbridge about 3 years ago and it's been great. If you just want them to filter spam and viruses, there's very little setup or maintenance needed, but you can get a lot of reports if you want or adjust settings if you want to implement a more tailored policy. In all the time we've used it, we might have gotten one false positive - in that instance, it wasn't clear if the blocked message was really what our guy was expecting. If your mail server is offline for maintenance, they hold your messages until you're back up. Jun 21, 2009 at 1:36

We use MessageLabs and find them to be very good.

I believe they meet all the criteria listed above too.


If you're interested in an appliance, I would highly recommend Barracuda Networks; their appliances do everything you ask and personally it's the best spam filtering I've ever used.


Three suggestions ...

My company has used the "MailWatch" service from InfoCrossing for over 7 years. It is excellent, and I recommend it highly. It works exactly as you describe in the picture, and requires virtually zero maintenance. I can't recall the last false positive, virtually no real spam gets through, and as a bonus it has two different A/V filters. Our MX records point to MailWatch and our firewall is secured to only allow SMTP from MailWatch IPs. It also filters outbound mail; our mail server is set to send all mail thru MailWatch and it will only accept mail for our domain from our IP address.

The Astaro ASG firewall line has embedded anti-spam in the firewall. It is not enabled in our ASG firewalls (because of MailWatch), but my experience with the company and the product leads me to think it will be good.

Finally, for a more off-beat recommendation .. Deep Six makes an interesting appliance, which uses a connection scoring mechanism (combining multiple black lists) rather than message analysis. It is highly recommended by Windows maven Bob Livingston.

  • do they have prices published anywhere?
    – galets
    Dec 21, 2009 at 0:45
  • Don't think so ... I can't say because of an NDA.
    – tomjedrz
    Dec 21, 2009 at 4:45

Checkout MX Logic. We looked at their service pretty closely at my last employer and I believe they eventually decided to use them. Their feature set is impressive and they seem to keep up with the "best of breed".


We have several years of experience with Spamsoap. www.spamsoap.com. You point your MX records to them. They have both active and aliased domains (aliased domains are free) and within those have both active users and aliases. Again, aliases are free.

Spamsoap provides both "core" and "enhanced" services. Core services include whitelisting, blacklisting, intelligent filtering, quarantine, virus filtering, file type filtering, etc. The filter sets can be default for the entire account, per domain, per group or even per user. Enhanced services include caching, in case your internal mail servers are unavailable, and even archiving and compliance reviewing and filtering. Also, they can provide outbound relay service.

They provide graphical metrics/reporting per domain.

You can opt to have each user receive a daily, weekly, or other quarantine listing with the ability to release and whitelist or blacklist senders from the quarantine listing.

Our users used to receive hundreds of spam messages per day. Spamsoap reduced this to virtually none. It's rare that anyone receives spam now, perhaps one per week, if that.

I have a number of friends that are very particular and want to "solve the problem" themselves. Those that have deployed spamsoap have found that the constant headache that was their spam load has simply gone away for the cost of a few dollars per mailbox per year. Additional justification is the bandwidth savings of not having to provide inbound capacity for the spam. In our network, the inbound spam was reaching a megabit per second, which more than pays for the Spamsoap cost.


i love mailcleaner. mailcleaner.org. works fantastically and is opensource.


Try http://www.safentrix.com. It with both Free and Paid models and does not have any Quarantine to manage.

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