Setup proxy with local CA certificate on Ubuntu 20.04

Green绿色

6/20/24, 11:37 AM

In our company, we have a proxy server with a self-signed CA certificate implementing MITM inspection. No internet connection is possible without this proxy server. My certificate installation process on a fresh install of Ubuntu server 20.04 (omitting sudo):

apt install ca-certificates
openssl x509 -inform der -in CompanyCA.cer -out CompanyCA.crt
openssl x509 -inform der -in CompanyRootCA.cer -out CompanyRootCA.crt
cp CompanyCA.crt CompanyRootCA.crt /usr/local/share/ca-certificates/
update-ca-certificates

This seems to have no effect. curl and wget still require the -k and --no-certificate-check options and apt's certificate verification fails. Timezone, date and time are set correctly.

Is there something else I could try (except ignoring it)?

210

0 + 6

ssl-certificate

curl

apt

ubuntu-20.04

symcbean

6/20/24, 2:10 PM

Check if the certificate has been added to /etc/ssl/certs/ca-certificates.crt, if not run update-ca-certificates with `-v`

captainmish

6/20/24, 3:30 PM

also check that the cert and chain is the one you expect with `openssl s_client -connect -showcerts`, or with `curl --cacert`

Alexander Pavluchenko

6/20/24, 3:34 PM

I suggest you also check the system logs for any error messages related to the certificate validation process. It's possible that there's another issue causing these errors.

Green绿色

6/21/24, 1:28 AM

@AlexanderPavluchenko Check the system logs with `dmesg`? I already checked `dmesg`, but didn't spot any errors relating to `apt`.

Green绿色

6/21/24, 1:42 AM

@symcbean I verified both certificates are in `/etc/ssl/certs/ca-certificates.crt`. But `curl` and `apt` still are complaining.

Green绿色

6/21/24, 1:52 AM

I solved this by copying over the certificates from another machine. Our company-internal docs are apparently outdated and are recommending old certificates.

Elon Musk

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EN: Setup proxy with local CA certificate on Ubuntu 20.04

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