BIND 9 upgrade behind BT DNS issues

Webmasters, check your configs

Several domain hosting companies have reported DNS errors coming from BT's doors in recent weeks. After failing to get any explanation from the monster telco, some contacted The Register in frustration.

Perhaps BT would be more co-operative with us. Err no.
But following our article earlier this week, we think we now have the definitive reason for the DNS problems experienced by many in the last couple of weeks.

BT has upgraded some of its name servers to BIND 9 which is stricter in enforcing standards and doesn't overlook configuration errors made by many hosting companies, which are the real cause of the problem.

In the case of NSDesign's name servers, for example, problems arose because it failed to contain name server records for their domain defined within the domain, counting on inheritance from the ".net" Top Level Domain. That's not tolerated in BIND 9.

Some of BT's DNS servers are running older versions of BIND which are less sensitive to misconfigurations of remote servers, so surfers connecting through BT servers running BIND 8 wouldn't see a problem. Trouble -free connections were also secured when surfers logged on through ISPs other than BT, again because DNS lookups went through servers running older versions of BIND.

BT outsources the running of their DNS servers, which seems to be reason why it proved so frustratingly hard to get an answer on our query. Further muddying the waters were admissions by BT support staff, when pressed, that the telco could be to blame for the problem.

Our story illustrated an important point for Web admins to bear in mind as use of BIND 9 becomes more commonplace.

Just to reiterate, this problem didn't just apply to site hosted by NSDesign and uksecurewebhosting.net but to some of the biggest tech sites on the net.

Thanks to all those who wrote in to set the record straight. ®

External Links

Posting by Cricket Liu, of DNS specialists Men & Mice, to BIND 9 user group which explains the issue in more technical detail

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