Nameserver messages on tor's logfile

[Hans de Hartog <dehartog@xxxxxxxxxx>]

Hi,

Tor's logfile irregulary receives the following messages:

May 01 20:38:14.542 [warn] eventdns: All nameservers have failed
May 01 20:38:15.034 [notice] eventdns: Nameserver 127.0.0.1 is back up
May 01 20:52:01.832 [warn] eventdns: All nameservers have failed
May 01 20:52:02.942 [notice] eventdns: Nameserver 127.0.0.1 is back up
May 02 09:23:49.074 [warn] eventdns: All nameservers have failed
May 02 09:23:49.503 [notice] eventdns: Nameserver 127.0.0.1 is back up
May 02 12:52:15.519 [warn] eventdns: All nameservers have failed
May 02 12:52:25.533 [notice] eventdns: Nameserver 127.0.0.1 is back up
May 02 12:53:52.209 [warn] eventdns: All nameservers have failed
May 02 12:53:52.296 [notice] eventdns: Nameserver 127.0.0.1 is back up

I'm running tor 0.2.0.34 on FreeBSD 7.1-RELEASE and FWIW, I'm also
running the standard nameserver locally: BIND 9.4.2-P2.
It started after being up (as exit-relay) for about 8 days and after 
that, I see
those messages several times per day. My libevent-version is 1.4.10
Why is this happening? I don't see anything logged by the nameserver so
it must be libevent who thinks that the nameserver fails.
Something to worry about? Or can I simply ignore those messages?

Thanks for your time,
Hans.