Hostname - Mail, etc.
I am trying to figure out something about hosting and domain name... my systems hostname right now are all hostnamexx.mydomain.com
I was investigating another ISPs and detected that their server differs from his internet domain name... if I check headers of mails, for example, I detect that a mail was sended by "xserver.anotherdomain.com", and that server is owned by "ispcompany.com".
Is there a problem if my registered domain is the same domain for all the machines? (in hosts, as part of the fqdn) or it should be different? please... if my english sucks, please tell me... (i will try to explain myself better is that is the case)
Thanks in advance, in a few days I will need to define the hostnames of my servers, I depend, right now, from your answers XD