My second domain name is recognized by the browser only prefixed with www !!!!

[Daniel Pope]

Hello,
Probably this is not the proper forum to post such a question but I think
this is related to.
Thanks to the help of the people of this list I setup my first domain name
and this works finely.
When I tried with the second one (otherdomain.com registered with
networksolutions) I had to do a virtual hosting and I got a strange problem:

Even if  both  www.otherdomain.com  and otherdomain.com are resolved ( I can
ping them from anywhere), my browser recognizse only www.otherdomain.com and
not other otherdomain.com.
That is pretty strange and I didn't find anyhing in the Apache and Linux 6
(I'm using them)  documentation.
Any help  would be very appreciated !