DoH behind nginx error: SSL: error:1408F119:SSL routines:SSL3_GET_RECORD:decryption failed or bad record mac

[CalunVier]

Nginx Version:

nginx version: nginx/1.20.1
built by gcc 5.4.0 20160609 (Ubuntu 5.4.0-6ubuntu1~16.04.12) 
built with OpenSSL 1.0.2g  1 Mar 2016
TLS SNI support enabled
configure arguments: --prefix=/etc/nginx --sbin-path=/usr/sbin/nginx --modules-path=/usr/lib/nginx/modules --conf-path=/etc/nginx/nginx.conf --error-log-path=/var/log/nginx/error.log --http-log-path=/var/log/nginx/access.log --pid-path=/var/run/nginx.pid --lock-path=/var/run/nginx.lock --http-client-body-temp-path=/var/cache/nginx/client_temp --http-proxy-temp-path=/var/cache/nginx/proxy_temp --http-fastcgi-temp-path=/var/cache/nginx/fastcgi_temp --http-uwsgi-temp-path=/var/cache/nginx/uwsgi_temp --http-scgi-temp-path=/var/cache/nginx/scgi_temp --user=nginx --group=nginx --with-compat --with-file-aio --with-threads --with-http_addition_module --with-http_auth_request_module --with-http_dav_module --with-http_flv_module --with-http_gunzip_module --with-http_gzip_static_module --with-http_mp4_module --with-http_random_index_module --with-http_realip_module --with-http_secure_link_module --with-http_slice_module --with-http_ssl_module --with-http_stub_status_module --with-http_sub_module --with-http_v2_module --with-mail --with-mail_ssl_module --with-stream --with-stream_realip_module --with-stream_ssl_module --with-stream_ssl_preread_module --with-cc-opt='-g -O2 -fPIE -fstack-protector-strong -Wformat -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -fPIC' --with-ld-opt='-Wl,-Bsymbolic-functions -fPIE -pie -Wl,-z,relro -Wl,-z,now -Wl,--as-needed -pie'

dnscrypt-proxy version: 2.1.5

part of nginx configuration about dnscrypt-proxy:

server {
    listen       443 ssl;
    ssl_certificate chained.crt;
    ssl_certificate_key private.key;
    ssl_protocols TLSv1.2 TLSv1.3;

    location / {
        # Some irrelevant information
    }

    location /dns-query {
        proxy_redirect off;
        proxy_set_header Host $http_host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-NginX-Proxy ture;
        proxy_set_header X-Forwarded-Proto $scheme;
        proxy_ssl_trusted_certificate /root/dnscrypt/localhost.pem;
        proxy_ssl_protocols TLSv1.2;
        proxy_pass https://127.0.0.1:3000;
    }
}

I tried my best to get the configuration right, and I even trusted localhost.pem. But I still find some error messages in nginx's error.log:

2023/08/29 17:06:37 [error] 32441#32441: *8405 SSL_read() failed (SSL: error:1408F119:SSL routines:SSL3_GET_RECORD:decryption failed or bad record mac) while reading response header from upstream, client: {my computer ip}, server: {dnscrypt-proxy hosted ip}, request: "POST /dns-query HTTP/1.1", upstream: "https://127.0.0.1:3000/dns-query", host: "{dnscrypt-proxy hosted ip}"

Sometimes DNS queries fail, and I suspect this is related to the error which is reported by nginx. I don't know that these situations should be improved.

Has anyone had a similar experience?

[lifenjoiner]

Why not use local_doh directly? Although it is named and described with local prefix, it works with WLAN and public IPs.

[CalunVier]

Because I only have one public ip and only one 443 port. HTTPS service is running too.

[lifenjoiner]

Try (other ports) to narrow down the issue range?
I guess it is more likely at nginx. I saw dozens of error:1408F119 on the web.