Single domain SSL certificate installed in subdomain shows in another subdomain

Server information :

Ubuntu 14.04 Apache2, Mysql, PHP7

Control Panel ISPConfig 3.1

Single IP for all domain

I have installed and runing :


sub1.domain.ltd sub2.domain.ltd sub3.domain.ltd sub4.domain.ltd sub5.domain.ltd and so on

As in title i had buy from RapidSSL Single SSL certificate for single domain sub1.domain.ltd

but when i check the sub2.domain.ltd

None of the common names in the certificate match the name that was entered (sub1.domain.ltd). You may receive an error when accessing this site in a web browser. Learn more about name mismatch errors.

Is it installing error. how to install it. how to install it correct way

or each sub domain can't own it's individual ssl certificate or it's IP metter


When you have a single server with multiple SSL/TLS hostnames, then there are only a few ways to do it successfully:

  • a single certificate, with all the hostnames listed as Subject Alternative Names (SAN - a certificate extension)
  • or multiple certificates, with both the server and the clients supporting SNI (Server Name Indication - a SSL/TLS protocol feature) and each certificate associated with a specific named virtual host
  • or multiple certificates, each certificate on its own service or Apache virtual host, each assigned to a separate IP address

The last option is the most legacy-compatible, but obviously difficult to implement as it may not be easy to get multiple public IP addresses for a single server today.

The second option is probably what you're planning to use, but either your client or server is missing SNI support or there is a configuration error.

Check your Apache error log. If it says:

You should not use name-based virtual hosts in conjunction with SSL!!

when you start Apache, then your version of Apache does not have SNI support. If SNI support exists in Apache, it should say:

[warn] Init: Name-based SSL virtual hosts only work for clients with TLS server name indication support (RFC 4366)

See this page in Apache wiki for more details.

Wikipedia has a list of web server and browser versions that introduced SNI support.

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