OpenSSL SSL_connect: SSL_ERROR_SYSCALL A system call error occurred in the connection to domain.com:443.

Question

I used the curl command on the Ubuntu terminal and got the following response: curl: (35) OpenSSL SSL_connect: SSL_ERROR_SYSCALL in connection to domain.com:443. I really can't understand why this happens. I tried displaying curl's error number but no number was returned. I'm accessing another server. Here are my commands:

./curl -i --tlsv1.2 -kv -H "Content-Type: application/xml" --verbose -X POST --data / var/www/html/xml.xml --cacert /root/curl_ssl/curl-7.54.1/src/cert_org.crt domain.com/otp

Is there any way

Answer 1

For websites using the old SSL protocol, this error may occur when using CURL on Linux. According to the SSL/TLS protocol specification, the cause may be that the client hello uses a support group option that is not supported by the peer. The solution is to use sslscan to probe and get the protocol version and cipher suites supported by the peer. You can find sslscan on Github.