Xtra has had all its mail servers removed from the anti-spam Realtime Blacklist – but has done so without completely closing its SMTP relay.
The pool of servers which constitutes smtp.xtra.co.nz will still relay mail from some New Zealand IP addresses which are not Xtra dial-ups, but they are closed to relaying from overseas addresses, according to Xtra's business manager for access, Andy Miller.
"We've gone from relaying mail from a broad range of IP addresses to a narrow range," says Miller.
Neither of the country's other two largest ISPs, the Internet Group (Ihug) and Clear Net, runs an open relay. Clear Net never has, and Ihug stopped last year after serious abuse of its mail servers by US-based junk mailers.
It was spam originating in the US and relayed via one Xtra SMTP server, terminator.xtra.co.nz, which got Xtra onto the Realtime Blacklist, which is described by its operators – the Mail Abuse Protection System (MAPS) - as "a system for creating intentional network outages for the purpose of limiting the transport of known-to-be-unwanted mass e-mail."
Any site is free to subscribe to the RBL. Several thousand domains choose to apply a block on traffic from all IP addresses on the list, others merely to log traffic from suspect sites. Most IP addresses make the list because they are those of open SMTP relays.
Senders of bounced mail get back a message explaining that their mail has been refused and directing them to the MAPS RBL Website, which carries background information as well as a text entry on every site on the list.
Site information suggests users contact their ISPs and assures them that "correcting this problem is usually a very simple process, involving your ISP changing a few lines of one configuration file, or ticking a checkbox on a configuration form."
In Xtra's case, however, it took nearly two weeks to sort out. Why? In the first instance because Xtra made no response to several messages sent to firstname.lastname@example.org by Brian J. Murrell of InterLinx Support Services in Canada. Murrell received unsolicited mail that had been relayed via terminator.xtra.co.nz. He informed Xtra that its sever had been "hijacked by spammers" and noting that "information on the prevention of unauthorized relaying can be found at maps.vix.com/tsi."
Murrell nominated the Xtra server for the list after three messages at four day intervals had gone unanswered. Local anti-spam camapginer Alan Brown of Manawatu Internet services broke the news, and the local Internet's chattering classes dined out on Xtra's mishap.
Xtra moved to get off the list – by taking down the offending server and replacing it. Miller says this was just a simple, quick way of fixing the problem – "we took the machine that was blacklisted out of the loop … We notified these guys and said, this is what we're doing.".
Brown and others saw Xtra's action as a switch of IP addresses to get around the list. Subsequently, Brown says, he contacted the MAPS people "to say that these guys are relaying and they've sidestepped it. The response I got back from Dave Rand was that he wasn't particularly interested, but Paul Vix ended up putting them in the RBL a few days later."
This time, Xtra had a whole block of IP addresses in the blacklist, and Miller was most unhappy.
"I though it was pretty nasty. We actually had some sites that we were blocking from a relay point of view, and those were sites that our customers had complained to us about. We thought that was a responsible and reasonable way to do it."
Brown is unrepentant, saying he's "got to wonder how much the spammers are paying them … They had four months of warnings. I told them in February that they were relaying. They were repeatedly warned by people that they were spamming, and they continued to let it through.
Opinions are unlikely to converge on the relaying issue. Xtra has been pilloried in the newsgroups, but one ISP manager admits he has some sympathy with his giant competitor.
"Some people see the whole RBL thing as a bit too draconian – not everybody wants to go that far," he says. "You can imagine how many Xtra customers would be seriously inconvenienced if they close their mail relay."