Turns out the no-downtime-needed DNS maintenance needs downtime, since builds-4hr and pending.js and running.js are all failing, so tbpl can't show what's happening. Closed all trees (except try, they can make their own luck) at 2013-09-19T16:34:01.
We're working with IT to fix this up. Unexpected complications related to the DNS work in SCL1.
Thu 16:47:27 PDT  builddata.pub.build.mozilla.org:http file age - /buildjson/builds-4hr.js.gz is OK: HTTP OK: HTTP/1.1 200 OK self-serve is working too.
sheriffs, we're all OK from our side. Please reopen at your discretion. digi, could you let us know what went wrong ?
Still closed, waiting for Windows build slaves with working DNS.
Adam Newman is working on the firewall/network issue that's preventing w64-ix-slave*.winbuild.scl1.mozilla.com from reaching the new DNS servers.
Which is now resolved. The DNS server was responding on an different interface from what had received the request.
Because I'm not even half-sane, reopened at 2013-09-19T17:59:07 despite inbound being 15 pushes behind for Windows builds. Heck, how often do we break Windows? Oh, yeah, every 7 or 8 pushes.
:nthomas Please se https://bugzilla.mozilla.org/show_bug.cgi?id=917678#c8 for a description of the problem which caused the tree closure.