I/o timeout on DNS lookups while using split DNS

SUPPORT QUESTIONS
1

Tailscale version:

1.22.1
  tailscale commit: 0bc2caf8ce8fd4c471a3226ec1877ae0564429b1
  other commit: 988e8ad4342582d6d729bb2242cc062776b6b9fe-dirty
  go version: go1.17.8-tsdce70b6d32

Your operating system & version: Big Sur (macOS) Version 11.6 (20G165)

I’m using tailscale on my mac with a subnet router( with a 10.0.0.0/8 subnet) running inside a k8s cluster so I can access private resources within the cluster.

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These are my tailscale DNS settings.

Sometimes, the DNS lookup fails with:

2022/03/30 18:23:24 failed DNS query: lookup dpg-..svc.cluster.local on 8.8.8.8:53: read udp 100.72.132.49:58994->10.131.0.10:53: i/o timeout

These are the application logs from my mac from before and after the above error:

log show --color=auto --start "2022-03-30 18:20:0" --end "2022-03-30 18:25:0" | grep "tailscale" 

2022-03-30 18:20:56.500041-0700 0xa69a872  Default     0x0                  232    0    symptomsd: (SymptomEvaluator) [com.apple.symptomsd:netepochs] defusing ticker tickerFatal having seen progress by flow for io.tailscale.ipn.macos.network-extension, rxbytes 4969 duration 58.607 seconds started at time: Wed Mar 30 18:19:57 2022
2022-03-30 18:21:56.549956-0700 0xa6a6f86  Default     0x0                  232    0    symptomsd: (SymptomEvaluator) [com.apple.symptomsd:netepochs] defusing ticker tickerFatal having seen progress by flow for io.tailscale.ipn.macos.network-extension, rxbytes 5088 duration 60.053 seconds started at time: Wed Mar 30 18:20:56 2022
2022-03-30 18:22:56.649332-0700 0xa6a6f86  Default     0x0                  232    0    symptomsd: (SymptomEvaluator) [com.apple.symptomsd:netepochs] defusing ticker tickerFatal having seen progress by flow for io.tailscale.ipn.macos.network-extension, rxbytes 5009 duration 60.057 seconds started at time: Wed Mar 30 18:21:56 2022
2022-03-30 18:23:56.758403-0700 0xa685361  Default     0x0                  232    0    symptomsd: (SymptomEvaluator) [com.apple.symptomsd:netepochs] defusing ticker tickerFatal having seen progress by flow for io.tailscale.ipn.macos.network-extension, rxbytes 4968 duration 60.061 seconds started at time: Wed Mar 30 18:22:56 2022
2022-03-30 18:24:56.899468-0700 0xa685361  Default     0x0                  232    0    symptomsd: (SymptomEvaluator) [com.apple.symptomsd:netepochs] defusing ticker tickerFatal having seen progress by flow for io.tailscale.ipn.macos.network-extension, rxbytes 4929 duration 60.065 seconds started at time: Wed Mar 30 18:23:56 2022

Could you help me understand possible causes for the lookup failures?

2

I’d suggest turning on “Override local DNS” That makes sure the OS, and not just Tailscale uses the tailscale DNS settings.

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