How does prefixed domain name work?

[Barry Margolin]

In article <c1e6hr$1e7l$1 at sf1.isc.org>, mfrie01 at pobox.com (Michael) 
wrote:

> This weekend we moved our web site host to a new hosting company. For
> discussion, we'll use "domainname.com" as our site address. Clients
> log into a server behind our firewall through a link on our home page.
> There used to be an IP address in the home page link for client login,
> but it was changed recently and the developer has disappeared. The
> link now says https://secure.domainname.com/servername/
> 
> Now that we're with the new hosting company, the link is broken (no
> surprise). There's a security certificate on the client site that
> expect you to be at https://secure.domainname.com/servername/ and
> burps if you use the IP address. (But the IP address still works
> fine.)
> 
> Can someone tell me how a prefix to my domain name works so I can do
> whatever's necessary to get this thing working again?

You need an A record in the domainname.com zone file that translates the 
host name "secure" to the IP address of your server, i.e.

secure IN A <ipaddress>

-- 
Barry Margolin, barmar at alum.mit.edu
Arlington, MA