Telstra claims it has been taken off notorious Internet blacklists following its closure of a number of customer-operated mail servers that allowed spammers to liberally distribute bulk emails.

-We were testing it yesterday and we're confident Telstra's not on [any] blacklists anymore," Telstra representative Stuart Gray told ZDNet Australia.

ZDNet Australia reported yesterday that at least one BigPond mail server had been incorrectly configured to operate as an -open-relay" system, allowing anyone to relay outgoing mail from the server whether they were a BigPond customer or not.

Such glitches give free reign to cheeky spammers who search for open relay servers from which to freely distribute unsolicited bulk emails. Insecure servers of this kind can be blacklisted by other network administrators to block incoming spam, but unfortunately blacklisting can also cause innocent messages to bounce back to the sender.

Telstra claimed today that the mishap was caused by a number of customers on volume-based plans who created mail servers and -inadvertently left them open", resulting in the distribution of spam from BigPond mail servers.

-When we've called them [customers] they don't know it's going on...we've taken them through the process of closing down [open] mail relays," Gray said.

Telstra claims it was blacklisted for a -matter or days" and that, although it would have had a noticeable impact, only a very small percentage of BigPond customers would have been affected by emails that bounced back to their inbox.

Telstra said it was aware that it had to make changes to the process and allow users to set up mail servers so that the problem didn't rear its head again further down the track and make it necessary to close down the relay during set-up.

-We want to make sure that we don't allow this situation to occur," Gray said.

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