DNS MAIL SETTINGS

[Erhan]

Hi all,
I am comfiguring my dns MX records for use with my email server.
I added 1 MX record for my 1 mail server, configured my host for it,
and for the value I just put my domain name again (since I am usign a
dynamic ip it needs to resolve the ip from the hostname). The problem
is my mail server is not resolving my local domain name in DNS due to
inproper DNS settings. I have all the nessisary records (A, CNAME, and
MX set to prefrence of 5).

Any reason why my mail sever cannot resolve the domain name. ( I also
believe that it takes time for the dns setting to update, if this is
true it may be the source of my problem although I waited 20 minutes
after adjusting the settings.)

Last thing, is it possible to host the domain's servers on just 1
computer (Web, Mail, FTP, Telnet, DNS...(though mine is not on same
computer)...)?

Thanks in advance.