"All nameservers have failed" eventdns message

The symptom is messages appearing in the log after some uptime, usually several days:

Sep 11 10:42:30.665 [warn] eventdns: All nameservers have failed Sep 11 10:42:39.684 [notice] eventdns: Nameserver 4.2.2.1 is back up Sep 13 08:56:58.089 [warn] eventdns: All nameservers have failed Sep 13 08:57:01.788 [notice] eventdns: Nameserver 4.2.2.1 is back up Sep 13 08:57:03.089 [warn] eventdns: All nameservers have failed Sep 13 08:57:12.396 [notice] eventdns: Nameserver 4.2.2.2 is back up

After that tor process usually terminates without warning.

There are numerous reports about this issue on the net, just if you try to google that log message.

Trac:
Username: varnav