BTopenworld anti-spam measures introduced today are preventing customers with dynamic IPs from running their own mail servers.
The prohibition comes after that the ISP blocked inbound port 25 communications on all of its narrowband services (except Connect LAN with static IP address) and most of its broadband services. Of these only Business ADSL service with static IP option and Satellite services - both of which are expensive for mainstream consumers - are unaffected by the change.
BTo said it was only introducing policies already introduced by other ISPs. It said only a very small number of users would be affected by the changes, which it argues are part of the steps ISPs need to take in tackling the spam problem.
In a policy update, BTo explains that the move will prevent Internet Connection Sharing software that exposes your Internet session to the rest of the Internet from being used by spammers to send unsolicited emails.
The frustration from users over the move which they tell us was done without notice (BTo says its impractical to give notice on network changes made for operational reasons, like this).
Stewart Gilray told us the first he heard of the issue was when he came home and found his home mail server had died. Other users have similar complaints and express frustration in dealing with BTo support staff in connection with the move. Users question the effectiveness of the measure, which they argue is the wrong way of dealing with the problems open mail relays pose in the overall spam problem.
Adam Davies expresses widespread concerns that the change will make it too expensive for him to run his home mail server using his BTopenworld account.
"This affects all narrowband and broadband users unless they are on a static IP," he told us. "If you aren't on a static IP then unless you pay them an extra £30 per month you have to use their own mail servers which are notorious for going down and losing your mail".
A spokesman for BTo said the port blocking was separate from its recently announced agreement to use anti-spam services from Brightmail. ISPs need to tackle the spam problem on multiple fronts, he argued, saying that BTo's policy would benefit most users. ®