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Sets the proxy issuer SSL certificate filename.

Component Version macOS Windows Linux Server iOS SDK
CURL 10.3 ✅ Yes ✅ Yes ✅ Yes ✅ Yes ✅ Yes
MBS( "CURL.SetOptionProxyIssuerCert"; curl; Value { ; Encoding } )   More


Parameter Description Example Flags
curl The CURL session handle. $curl
Value The certificate file path. "/tmp/cert.pem"
Encoding The text encoding for text parameter.
Default is UTF-8.
Possible encoding names: ANSI, ISO-8859-1, Latin1, Mac, Native, UTF-8, DOS, Hex, Base64 or Windows. More listed in the FAQ.
"UTF8" Optional


Returns OK or error.


Sets the proxy issuer SSL certificate filename.
Pass a string naming a file holding a CA certificate in PEM format. If the option is set, an additional check against the peer certificate is performed to verify the issuer of the the HTTPS proxy is indeed the one associated with the certificate provided by the option. This additional check is useful in multi-level PKI where one needs to enforce that the peer certificate is from a specific branch of the tree.

This option makes sense only when used in combination with the CURL.SetOptionProxySSLVerifyPeer option. Otherwise, the result of the check is not considered as failure.

A specific error code (CURLE_SSL_ISSUER_ERROR) is defined with the option, which is returned if the setup of the SSL/TLS session has failed due to a mismatch with the issuer of peer certificate (CURL.SetOptionProxySSLVerifyPeer has to be set too for the check to fail).

See CURL.SetOptionProxyIssuerCertBlob to pass certificate as container or text.

See also PROXY_ISSUERCERT option in CURL manual.

See also

Release notes

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Created 24th June 2020, last changed 25th June 2020

CURL.SetOptionProxyHeader - CURL.SetOptionProxyIssuerCertBlob