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HTTPS Client intermittently fails to connect to cloudflare-dns.com (libcurl v8.5.0) #167

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pmharris77 opened this issue Jan 19, 2024 · 4 comments
Open

HTTPS Client intermittently fails to connect to cloudflare-dns.com (libcurl v8.5.0) #167

pmharris77 opened this issue Jan 19, 2024 · 4 comments

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@pmharris77
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I am having issues with the https client intermittently failing to connect (via curl) to cloudflare-dns.com after approx. 5 minutes of up time, resulting in a DNS reply outage from https_dns_proxy to my downstream DNS server.

After about another 5 minutes, the connection is then restored. This repeats in cycles.

I am using a Docker container using Alpine base image and v8.5.0 of libcurl.

Log output below.

Any ideas? Is v8.5.0 of libcurl not yet supported?

[I] 1705691664.509830 main.c:218 Version: 2023.12.27-8afbba7
[I] 1705691664.509843 main.c:219 Built: Jan 19 2024 19:13:15
[I] 1705691664.509873 main.c:220 System c-ares: 1.24.0
[I] 1705691664.557248 main.c:221 System libcurl: libcurl/8.5.0 OpenSSL/3.1.4 zlib/1.3 brotli/1.1.0 c-ares/1.24.0 libidn2/2.3.4 nghttp2/1.58.0
[W] 1705691664.678521 main.c:235 HTTP/3 is not supported by current libcurl
[I] 1705691664.687691 dns_server.c:57 Listening on 10.5.0.3:5053
[I] 1705691664.701509 main.c:308 DNS polling initialized for 'cloudflare-dns.com'
[W] 1705692511.570344 https_client.c:353 3C19: curl request failed with 0: No error
[W] 1705692511.570388 https_client.c:355 3C19: curl error message: Failed to connect to cloudflare-dns.com port 443 after 2 ms: Couldn't connect to server
[W] 1705692511.570405 https_client.c:382 3C19: No response (probably connection has been closed or timed out)
[W] 1705692511.570445 https_client.c:426 3C19: CURLINFO_OS_ERRNO: 99 Address not available
[I] 1705692511.570457 https_client.c:510 3C19: Response was faulty, skipping DNS reply.
@aarond10
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aarond10 commented Jan 23, 2024 via email

@pmharris77
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"99 Address not available" presumably means it's trying to bind to an address for the hostname (via gethostname()) that the docker container can't use. The fact it happens after 5 minutes is weird and possibly related to something else you have going on (NAT or VPN configuration perhaps).
…
On Sat, 20 Jan 2024 at 07:07, Paul Harris @.> wrote: I am having issues with the https client intermittently failing to connect (via curl) to cloudflare-dns.com after approx. 5 minutes of up time, resulting in a DNS reply outage from https_dns_proxy to my downstream DNS server. After about another 5 minutes, the connection is then restored. This repeats in cycles. I am using a Docker container using Alpine base image and v8.5.0 of libcurl. Log output below. Any ideas? Is v8.5.0 of libcurl not yet supported? [I] 1705691664.509830 main.c:218 Version: 2023.12.27-8afbba7 [I] 1705691664.509843 main.c:219 Built: Jan 19 2024 19:13:15 [I] 1705691664.509873 main.c:220 System c-ares: 1.24.0 [I] 1705691664.557248 main.c:221 System libcurl: libcurl/8.5.0 OpenSSL/3.1.4 zlib/1.3 brotli/1.1.0 c-ares/1.24.0 libidn2/2.3.4 nghttp2/1.58.0 [W] 1705691664.678521 main.c:235 HTTP/3 is not supported by current libcurl [I] 1705691664.687691 dns_server.c:57 Listening on 10.5.0.3:5053 [I] 1705691664.701509 main.c:308 DNS polling initialized for 'cloudflare-dns.com' [W] 1705692511.570344 https_client.c:353 3C19: curl request failed with 0: No error [W] 1705692511.570388 https_client.c:355 3C19: curl error message: Failed to connect to cloudflare-dns.com port 443 after 2 ms: Couldn't connect to server [W] 1705692511.570405 https_client.c:382 3C19: No response (probably connection has been closed or timed out) [W] 1705692511.570445 https_client.c:426 3C19: CURLINFO_OS_ERRNO: 99 Address not available [I] 1705692511.570457 https_client.c:510 3C19: Response was faulty, skipping DNS reply. — Reply to this email directly, view it on GitHub <#167>, or unsubscribe https://github.com/notifications/unsubscribe-auth/AABTOXVGFN7DHCEPHNVO7ELYPLG65AVCNFSM6AAAAABCCO6O7GVHI2DSMVQWIX3LMV43ASLTON2WKOZSGA4TCMZQGM3TQMI . You are receiving this because you are subscribed to this thread.Message ID: @.>

I thought it could be do do with my Docker network set up as you mention, but to rule it out, I changed my docker base image to Debian (which has older libcurl v7.88.1) and it works and never drops connection. As soon as I switch back to Alpine and libcurl v8.5.0, the upstream server connection instability comes back. Very strange.

@aarond10
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aarond10 commented Jan 25, 2024 via email

@pmharris77
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I don't think so. The image just has the https_dns_proxy binaries and runtime dependencies installed and Alpine is even slimmer than Debian so far as I understand.

Has it been tested with libcurl v8.5.0? Having said that, I'd be surprised if it was that since I read the major version change from v7 to v8 wasn't actually a major update and didn't break the API, it was just to reset the minor version numbers which were getting a bit too high.

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@aarond10 @pmharris77