HTTPS无法打开：curl: (35) Encountered end of file

访问HTTP可以，HTTPS无法打开

使用curl -I https://www.***.com 返回 curl: (35) Encountered end of file

[root@instance-3 ~]# curl -I https://www.***.com -vvv* About to connect() to www.***.com port 443 (#0)*   Trying 104.199.*.*...* Connected to www.***.com (104.199.*.*) port 443 (#0)* Initializing NSS with certpath: sql:/etc/pki/nssdb*   CAfile: /etc/pki/tls/certs/ca-bundle.crt  CApath: none* NSS error -5938 (PR_END_OF_FILE_ERROR)* Encountered end of file* Closing connection 0curl: (35) Encountered end of file

原因：服务器443端口未对外开放！