Strange nameserver fail warning in Tor log
I am running an exit relay on Linux, my Tor version is 0.2.4.21
I checked the log and found this strange warnings: Apr 24 15:14:07.000 [notice] Circuit handshake stats since last time: 91698/91698 TAP, 15988/15988 NTor. Apr 24 17:40:45.000 [warn] eventdns: All nameservers have failed Apr 24 17:40:45.000 [notice] eventdns: Nameserver :53 is back up Apr 24 18:01:51.000 [warn] eventdns: All nameservers have failed Apr 24 18:01:51.000 [notice] eventdns: Nameserver :53 is back up Apr 24 18:01:52.000 [warn] eventdns: All nameservers have failed Apr 24 18:01:53.000 [notice] eventdns: Nameserver :53 is back up Apr 24 18:02:00.000 [warn] eventdns: All nameservers have failed Apr 24 18:02:01.000 [notice] eventdns: Nameserver :53 is back up Apr 24 18:02:01.000 [warn] eventdns: All nameservers have failed Apr 24 18:02:01.000 [notice] eventdns: Nameserver :53 is back up Apr 24 19:46:22.000 [warn] eventdns: All nameservers have failed Apr 24 19:46:22.000 [notice] eventdns: Nameserver :53 is back up Apr 24 20:46:25.000 [warn] eventdns: All nameservers have failed Apr 24 20:46:25.000 [notice] eventdns: Nameserver :53 is back up Apr 24 21:14:07.000 [notice] Heartbeat: Tor's uptime is 8 days 12:00 hours, with 13940 circuits open. I've sent 549.49 GB and received 543.20 GB.
So I thought it's the fault of the nameservers provided by the ISP. Fair enough, I have configured my own resolver on localhost (where the relay is running) using BIND 9.10 (latest stable) with dnssec-validation and everything. I thought I fixed it. After some time, I checked the logs again and: Apr 24 23:26:03.000 [warn] eventdns: All nameservers have failed Apr 24 23:26:03.000 [notice] eventdns: Nameserver 127.0.0.1:53 is back up Apr 25 02:04:02.000 [warn] eventdns: All nameservers have failed Apr 25 02:04:02.000 [notice] eventdns: Nameserver 127.0.0.1:53 is back up Apr 25 02:04:03.000 [warn] eventdns: All nameservers have failed Apr 25 02:04:04.000 [notice] eventdns: Nameserver 127.0.0.1:53 is back up Apr 25 02:04:04.000 [warn] eventdns: All nameservers have failed Apr 25 02:04:05.000 [notice] eventdns: Nameserver 127.0.0.1:53 is back up Apr 25 02:04:06.000 [warn] eventdns: All nameservers have failed Apr 25 02:04:06.000 [notice] eventdns: Nameserver 127.0.0.1:53 is back up Apr 25 02:04:08.000 [warn] eventdns: All nameservers have failed Apr 25 02:04:08.000 [notice] eventdns: Nameserver 127.0.0.1:53 is back up
Looks like its something Tor related. Why do I get this warning? Does this have any penalty on the performance or over the users who are using this node as an exit point? Should I just leave it alone as it works fine? From what I see nameservers fail and get back online immediately, fail and back on have same timestamp. Advices? Thanks in advance.