INTERNET service provider (ISP) CyTA yesterday switched off a spam-email filtering services after legitimate users reported that it had blocked their emails and wanted money to release them.
CyTA was using a service called SORBS, which blocks emails coming from IP addresses that are known sources of spam.
However, in recent days SORBS appears to have added several legitimate IP addresses to its black-list, and were refusing to remove these users unless they paid a USD $55 ‘fine’ which is regarded in several internet forums as extortion.
Paphos resident Colin Pearson was one such user who discovered he was wrongly added to SORBS’ blacklist when he tried to send an email from Yorkshire in the UK to his solicitor in Cyprus.
Pearson said yesterday: “I only sent eight emails which I would not call spamming… If your email is part of a large service (for example AOL) and your IP address is shared you can be blacklisted due to no fault of your own and cannot be unlisted unless your ISP contacts SORBS and donates $25,000.”
After the same thing happened to several of his Yorkshire based friends, whose emails were being blocked and returned to sender by SORBS, Pearson contacted CyTA whose policy at that time was to integrate SORBS with several other methods.
CyTA systems engineer Constantinos Lyras said yesterday: “Unsolicited commercial emails, adverts, viruses and phishing scams make up around 90 per cent of all emails that are sent, and as a provider we want to eliminate as many as possible of these.”
Lyras said that every provider uses various techniques to block this, without which it would be impossible for anyone to do their job or use emails effectively. However, these inevitably produce ‘false positives’, i.e. legitimate emails that seem like spam.
Asked how CyTA tackles this problem, Lyras said: “We try to select rules that produce few false positives, and if a tool is producing many, we may relax or stop it. This is what we did this morning when we switched off SORBS.”
Alecos Alexandrou, who manages the CyTA’s data service centre in Nicosia said: “We detected a number of complaints – it seems SORBS have changed their filtering methods to become more aggressive.”
Nor is it just the smaller regional internet service providers that are affected. Alexandrou said that the big email firms such as Gmail, Yahoo and Hotmail have also found some of their email addresses are blocked. In order to be removed from this list, SORBS has reportedly requested these email providers pay USD$25,000. Until now they have refused.
CyTA’s cancellation will be good for news for anyone whose emails have been blocked in recent weeks, whether a spammer or a false positive, but it is too little too late for Pearson who has already cancelled his CyTA internet and telephone service.
Lyras estimates that around two million emails are sent and received in Cyprus every day, of which 1.8 million will typically be spam.
