End-user troubleshooting of bad c-ares interaction with router

[Nicholas Chammas]

Here’s the output of adig and ahost <https://gist.github.com/nchammas/a4c9873d8158c323796e9b47c064e63a#file-adig-ahost-txt>, both with and without the DNS servers set directly on the network interface (vs. just on the router).

I also learned that gRPC 1.60.0 may be using c-ares 1.19.1 <https://github.com/grpc/grpc/tree/v1.60.0/third_party/cares>, though again that’s just via looking at the gRPC source and not via some runtime query.


> On Jan 21, 2024, at 7:34 AM, Brad House <brad at brad-house.com> wrote:
> 
> I think homebrew distributes the 'adig' and 'ahost' utilities from c-ares.  Can you try using those to do the same lookup so we can see the results?
> 
> On 1/19/24 11:01 AM, Nicholas Chammas wrote:
>> 
>>> On Jan 17, 2024, at 3:38 PM, Brad House <brad at brad-house.com> <mailto:brad at brad-house.com> wrote:
>>> What version of c-ares is installed?
>>> 
>> Sorry about the delay in responding. Answering this question is more difficult than I expected.
>> 
>> I know that Spark Connect is running gRPC 1.160.0. Looking through the gRPC repo, I see mention of c-ares 1.13.0 <https://github.com/grpc/grpc/blob/v1.60.0/cmake/cares.cmake#L42>, but I don’t know how that translates to my runtime. Homebrew tells me I have c-ares 1.25.0 installed, but again, I’m not sure if that’s what I’m actually running.
>> 
>> Is there a way I can directly query the version of c-ares being run via Spark Connect / gRPC? I asked this question on the gRPC forum <https://groups.google.com/g/grpc-io/c/3tZCa48Xvh8> but no response yet.
>> 
>> For the record, I know that c-ares is involved because if I tell gRPC to not use it (via GRPC_DNS_RESOLVER=native <https://github.com/grpc/grpc/blob/b34d98fbd47834845e3f9cdaa4aa706f1aa4eddb/doc/environment_variables.md>) then my problem disappears.
>>> What DNS servers are configured on your MacOS system when its not operating properly?  The output of "scutil --dns" would be helpful here.
>>> 
>> Here’s that output. <https://gist.github.com/nchammas/a4c9873d8158c323796e9b47c064e63a#file-scutil-dns-txt> I believe 192.168.1.1 is just my local router, and on there is where I have the default DNS servers set to 1.1.1.1 and 1.0.0.1.
>> 

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