The cost of defending a network against spam and viruses is falling, according to one anti-spam company, just as another says the problem has never been bigger.

Barracuda Networks has started selling its Spam Firewall appliances in the UK and is pushing its lower cost compared to competitors. Meanwhile, email filtering company Email Systems has published a survey claims that spam has reached 85 percent of total UK email.

Both are, of course, sales pitches in an increasingly competitive market. Nevertheless different philosophies and methods of dealing with spam are apparent from in-depth conversations we held with anti-spam leaders Barracuda and FrontBridge.

The spam survey, carried out during August by Email Systems, says spam was over 90 percent on six separate days last month, peaking at nearly 93 percent on Sunday 22 August. "We have also witnessed that the nature of spam is continuing to evolve, with pornography on the decline and drugs and gambling both significantly increasing," says Neil Hammerton, Email Systems' managing director. "Some of our clients would quite literally not be able to use email at all if they did not employ our system."

Both it and Barracuda claim to catch up to 98 percent of spam, but the increasing scale of the problem has also highlighted two very different ways of attacking it. On the one hand, a managed remote service; and on the other, a box that resides on the customer's site.

Barracuda's CEO Dean Drako claims that with prices from £1,950, plus typically £170 a year for updates and no per-user licencing fees, his boxes can be 20 to 40 times cheaper to own and run than similar appliances from rivals such as BorderWare and ProofPoint.

The Barracuda box is not a traditional proxy, he adds - it sits behind the firewall, you point your MX record to it and tell it where to forward the mail next. "It typically reduces the load on the mailserver by half, and the savings from that are enough to pay for the box," he says.

Draco adds that a layered approach is what enables Barracuda to make its appliances cheaper than the competition. "We have 10 layers of spam defence," he says. "The early layers are very low CPU overhead so we can use lower cost hardware" to filter out the bulk of the rubbish before the hardwork starts. "We also do our own manufacturing - we have invested heavily in build-to-order manufacturing, similar to the Dell model. A third reason is that none of the technology is licenced, so we don't pay any licence fees to others."

However, another managed service provider stressed the advantages of outsourcing in an area as fast-moving as email. "It is extremely difficult for IT managers to keep up," said Jesse Villa, technical product manager at messaging services provider FrontBridge.

He added that a managed solution requires no local client software or support, for example, and could also support Blackberries and Palms without extra effort on the customer's part. "The other thing it eliminates is the infrastructure cost," he said. "A service requires no infrastructure investment from sender or receiver."

Read the interview with Barracuda and FrontBridge here.