Following in the footsteps of BT? It would appear so...Customers of UK ISP Freeserve are complaining that their emails appear to have fallen foul of a spam blacklisting. Mail delivery failure notifications are pointing users towards DSBL.org - the distributed server boycott list - which maintains a list of servers which are "dangerously misconfigured" in such a way as to lend themselves to spammers through the abuse of open relays. Such a blacklisting effectively means servers at the UK's most popular ISP have been identified as a source of spam, though Freeserve denies its servers permit open relay and rejects the suggestion that it is responsible for spam. silicon.com was alerted to the problem by reader Iain Sommerville, who started experiencing problems in the past week. In an email, DSBL.org told Sommerville: "The servers that are [blacklisted] are Freeserve's mail servers. A security issue allowing spammers to abuse any of Freeserve's customers' machines could have resulted in their outgoing mail servers being listed in the DSBL list." Sommerville told silicon.com the problem, while intermittent, has knocked his confidence in using email - as it increases concerns that his messages may not be getting through. "If this is a problem with Freeserve's servers then it is obviously a little bit worrying, especially if they are not meeting the requirements set out by DSBL," he added. A spokeswoman for Freeserve said: "Our network service provider does not allow open relay on our platform and takes measures to reduce the impact of spam both incoming and outgoing. We will work with our network service provider to investigate the issue and minimise any possible inconvenience to customers." In June BT fell foul of the DSBL service which is referenced by some anti-spam filters - meaning that a number of BT Openworld customers experienced the problem of emails bouncing back, wrongly identified as spam, because the server they were using was blacklisted. Once made aware of the problem by silicon.com BT was quick to remedy the situation. Have you had problems with a blacklisted ISP? If so, let us know by emailing email@example.com.