jekkil wrote:
-DNS settings are configured separately but share an IP
-vhosts are individually configured, there is no default vhost
- httpd.conf file is accessible for me, I have root access, but being new in the self managed server experience, if you could tell me what to look for in the file, it could help determine if I can do something.
I'm not sure that the following description is your case, but it's an example of the same issue.
Let's assume that a user has a domainname domain.com and he setups dns for wildcard subdomains (*.domain.com) and add *.domain.com as alias in httpd.conf (currently it's first and only virtual host here). Now any subdomain.domain.com points to the same website. Then the same user adds domain2.com to dns and httpd.conf, but dns uses wildcards subdomains and httpd.conf doesn't include *.domains2.com as alias to domain2.com. Now when browser goes to subdomain.domain2.com, dns resolves this address to IP address of the server, but httpd.conf doesn't contain record for subdomain.domain2.com and will use first record from httpd.conf, that is domain.com.
PS. And note that vhosts.conf is a part of httpd.conf.