Require Specific FTPS Server Certificate Fields

See more FTP Examples

Demonstrates the Chilkat Ftp2.SetSslCertRequirement method, which adds a required match against the FTP server certificate. The first argument selects the certificate field (such as SubjectCN or IssuerCN) and the second is the required value. It is a void method; a non-matching certificate causes the connection to fail.

Background: Standard TLS validation confirms a certificate is trusted and valid for the hostname, but it does not guarantee you reached the specific server you expect — a form of pinning closes that gap. Requiring a certificate field to match a known value rejects any certificate that does not, defending against a mis-issued or substituted certificate even if it would otherwise pass validation. Multiple requirements can be added, and all must be satisfied.

Chilkat Go Downloads

Download Chilkat for Go

    success := false

    //  Demonstrates the Ftp2.SetSslCertRequirement method, which adds a required match against the FTP
    //  server certificate.  The 1st argument selects the certificate field and the 2nd is the required
    //  value.  It is a void method.

    ftp := chilkat.NewFtp2()

    ftp.SetHostname("ftp.example.com")
    ftp.SetUsername("myFtpLogin")

    //  Normally you would not hard-code the password in source.  You should instead obtain it
    //  from an interactive prompt, environment variable, or a secrets vault.
    ftp.SetPassword("myPassword")

    //  Use explicit FTPS (AUTH TLS) on the standard FTP port.
    ftp.SetAuthTls(true)

    //  Require that the server certificate's subject common name matches an expected value.  If the
    //  presented certificate does not match, the TLS connection fails.  Supported fields include
    //  SubjectDN, SubjectCN, IssuerDN, IssuerCN, and others.
    ftp.SetSslCertRequirement("SubjectCN","ftp.example.com")

    success = ftp.Connect()
    if success == false {
        fmt.Println(ftp.LastErrorText())
        ftp.DisposeFtp2()
        return
    }

    fmt.Println("Connected; server certificate met the requirement.")

    success = ftp.Disconnect()
    if success == false {
        fmt.Println(ftp.LastErrorText())
        ftp.DisposeFtp2()
        return
    }


    ftp.DisposeFtp2()