BTopenworld has responded to being put on a spam blacklist by tweaking its servers in a move it hopes will pacify angry users and the people behind the blacklist.
Spam is increasingly frustrating computer users
Blacklist services are becoming more common as a way of avoiding or significantly reducing spam.
Internet Service Providers, (ISPs), that have signed up to the Distributed Server Boycott List do not receive mail from servers that the group deems to be misconfigured, insecure or abuseable.
Embarrassingly for BT it is included on the list meaning that a small proportion of its business customers find that e-mails sent to certain ISPs bounce back.
Now BT has put a fix in place that should resolve the problem uncovered by the DSBL, although it is not convinced that it will be removed from the blacklist.
A BTopenworld spokesman said that the company was having problems communicating with the blacklist authors.
"Such groups have good intentions but can create problems for ISPs and customers that are exaggerated well beyond the nature of the glitch they have uncovered," he added.
Nick Truman is Head of Customer Security for BTopenworld.
He said BT had been unfairly targeted by DSBL and that the group would have had to "seriously reconfigure their e-mail service" in order to find the spam vulnerability.
In common with other ISPs, around 40% of e-mail passing through BTopenworld's system is thought to be spam.