Basically, I go ahead and get the domainname from a provider and
then set things up from there.  I use ehost.com, which works ok, but
if you have someone better, then go with them.  At ehost, we pay for
"domain dashboard", which is probably not required, but it makes
it easier to set up dns.  Using domain dashboard, we can redirect
traffic as we see fit.  It might be possible to just redirect all
traffic from a domain to an IP address and get that to work.

There are several steps.

<ol>
<li> I have a machine with a .eecs.berkeley.edu address and a static
IP address.

<li> Because I have multiple websites, that machine is configured using
virtual ip interfaces to answer to multiple ip addresses.  This is
where I get into trouble with Mark and the department, then are
resistant to having multiple IP addresses on a single machine because
of a perceived shortage of IP addresses.  I use multiple ip addresses
on one machine for two reasons:
<ul>
  <li> It means that the machine has a canonical name that "always
  works" even if the domain registrar messes up
  <li> I can have one machine host multiple sites.
</ul>
The reasons we need multiple IP addresses is because SSL does not
always work from corporate firewalls to ports other than 447

However, you might not need multiple IP addresses, you could probably
get away with one address in the short term.

<li> The machine is running a webserver that listens on the appropriate
IP addresses and has the appropriate aliases.


<li> The domains provider (ehost) maps traffic meant for my domain
to the ip address of my host or I have a CNAME
</ol>

In this example, I have ehost's dns entry set up so traffic for
www.truststc.org has a CNAME to trust.eecs.berkeley.edu:

<pre>
bash-3.00$ dig any www.truststc.org

; <<>> DiG 2.0 <<>> any www.truststc.org
;; ->>HEADER<<- opcode: QUERY , status: NOERROR, id: 6
;; flags: qr rd ra ; Ques: 1, Ans: 1, Auth: 2, Addit: 0
;; QUESTIONS:
;;      www.truststc.org, type = ANY, class = IN

;; ANSWERS:
www.truststc.org.       3600    CNAME   trust.eecs.berkeley.edu.

;; AUTHORITY RECORDS:
truststc.org.   73797   NS      ns2.ehost.com.
truststc.org.   73797   NS      ns1.ehost.com.

;; Sent 1 pkts, answer found in time: 92 msec
;; FROM: carson.EECS.Berkeley.EDU to SERVER: default -- 128.32.48.21
;; WHEN: Mon Apr 28 13:27:54 2008
;; MSG SIZE  sent: 34  rcvd: 116

bash-3.00$
</pre>

trust.eecs goes to 128.32.244.34 (except email, more on that below)
<pre>
bash-3.00$ dig any trust.eecs.berkeley.edu

; <<>> DiG 2.0 <<>> any trust.eecs.berkeley.edu
;; ->>HEADER<<- opcode: QUERY , status: NOERROR, id: 6
;; flags: qr aa rd ra ; Ques: 1, Ans: 2, Auth: 6, Addit: 7
;; QUESTIONS:
;;      trust.eecs.berkeley.edu, type = ANY, class = IN

;; ANSWERS:
trust.eecs.berkeley.edu.        86400   A       128.32.244.34
trust.eecs.berkeley.edu.        86400   MX      5 andrews.eecs.berkeley.edu.

;; AUTHORITY RECORDS:
eecs.berkeley.edu.      86400   NS      vangogh.CS.berkeley.edu.
eecs.berkeley.edu.      86400   NS      ns.CS.berkeley.edu.
eecs.berkeley.edu.      86400   NS      ns.eecs.berkeley.edu.
eecs.berkeley.edu.      86400   NS      cgl.UCSF.edu.
eecs.berkeley.edu.      86400   NS      adns1.berkeley.edu.
eecs.berkeley.edu.      86400   NS      adns2.berkeley.edu.

;; ADDITIONAL RECORDS:
andrews.eecs.berkeley.edu.      86400   A       128.32.244.30
ns.CS.berkeley.edu.     86400   A       169.229.60.61
ns.eecs.berkeley.edu.   86400   A       169.229.60.153
cgl.UCSF.edu.   62066   A       169.230.27.20
adns1.berkeley.edu.     153260  A       128.32.136.3
adns2.berkeley.edu.     153264  A       128.32.136.14
vangogh.CS.berkeley.edu.        86400   A       128.32.112.208

;; Sent 1 pkts, answer found in time: 0 msec
;; FROM: carson.EECS.Berkeley.EDU to SERVER: default -- 128.32.48.21
;; WHEN: Mon Apr 28 13:30:44 2008
;; MSG SIZE  sent: 41  rcvd: 315

bash-3.00$
</pre>

Andrews is my machine that is running the webservers, it has 3 virtual
interfaces, including the 128.32.244.34 address:
<pre>
andrews.EECS.Berkeley.EDU:root:> ifconfig -a
lo0: flags=2001000849<UP,LOOPBACK,RUNNING,MULTICAST,IPv4,VIRTUAL> mtu 8232 inde
x 1
   inet 127.0.0.1 netmask ff000000
bge0: flags=1004843<UP,BROADCAST,RUNNING,MULTICAST,DHCP,IPv4> mtu 1500 index 2
  inet 128.32.244.30 netmask ffffff00 broadcast 128.32.244.255
    ether 0:3:ba:c6:e7:a9
bge0:1: flags=1000843<UP,BROADCAST,RUNNING,MULTICAST,IPv4> mtu 1500 index 2
       inet 128.32.244.31 netmask ffffff00 broadcast 128.32.244.255
bge0:2: flags=1000843<UP,BROADCAST,RUNNING,MULTICAST,IPv4> mtu 1500 index 2
 inet 128.32.244.32 netmask ffffff00 broadcast 128.32.244.255
bge0:3: flags=1000843<UP,BROADCAST,RUNNING,MULTICAST,IPv4> mtu 1500 index 2
 inet 128.32.244.34 netmask ffffff00 broadcast 128.32.244.255
andrews.EECS.Berkeley.EDU:root: %C2> 

</pre>
For apache, the 128.32.244.34 ip address appears in files like:

<pre>
/usr/local/apache/conf/httpd-vhosts.conf:<VirtualHost 128.32.244.34:80>
/usr/local/apache/conf/rewrite.conf:RewriteCond %{HTTP_HOST}   ^128.32.244.34$
/usr/local/apache/conf/ssl.conf:<VirtualHost 128.32.244.34:443>
</pre>

Things get fairly tricky with sendmail.  We use
/etc/mail/virtusertable and /etc/sendmail.cw to get things going


So, bottom line, if you have a domain name, you should be able to have
your domain registrar forward all traffic to your website.
You can either do it via an IP address or a CNAME to another name.
It is better to use a CNAME if you can because if your IP address
changes on campus then things will work seamlessly.  Also, you need
to set up both your www.yourdomain.org and yourdomain.org to go to
your machine.

<p>You can use apache rewrites to redirect traffic so that
http://ramp.eecs.berkeley.edu get redirected to your http://yourdomain.org