bgp's questions

I purchased a used "Rackable Systems" server off eBay and I discovered to my surprise when it arrived it has power connectors which appear to require ~48 volts DC input. It looks like this:

What sort of adapter is normally used to plug this into regular 110v AC power (normal "wall plug" power in the United States)?

EDIT:

My question is specifically what is this power connector called? - different from AC Input for 48 Volt DC Powered Server which is asking how to hook it up (a question which was never answered with anything other than, essentially, "get a new server").

After some searching I've come up totally empty handed on if there is any standard (or non-standard for that matter) specification or best practice for specifying the IMAP server for a domain name. I.e. if I have an account such as "[email protected]", and I wish to read my mail via IMAP, is there any DNS record which would indicate to my mail client which mail server it should be contacting? I've never seen anything like this, and virtually all email setup instructions I've seen include an exact host name for IMAP, e.g. "mail.example.com" or "imap.example.com". I guess the assumption is that the employees or other users of example.com can find out what server to use from their administrator. However if example.com were to have thousands of accounts, this would become burdensome. It would seem very useful to just enter your email address "[email protected]" and have it look up the IMAP server name in DNS based on the email's domain name (not dissimilar to how an MX record works for SMTP).

Anyone heard of anything like this?

TLDR: when I make this DNS record:

whatever.mydomain.com.  IN CNAME biglongjibberstring.r89.cf2.rackcdn.com.

How does Rackspace know that this random host name I've chosen should go to my Cloud Files container/account as opposed to another customer?

I just tested a simple example of using Cloud Files with Rackspace. I made a Cloud Files "Container" and enabled the "Static Website" option. I uploaded an example image and an example index.html file. These files in this container are now available at this crazy-long URL, which the UI tells me I can use as the CNAME for my domain:

And sure enough, adding a CNAME record like:

whatever.mydomain.com. IN CNAME biglongjibberstring.r89.cf2.rackcdn.com.

Browsing to http://whatever.mydomain.com/ works (tested the home page and the image). But how could it possibly know that when it sees a request for "whatever.mydomain.com" (in the HTTP Host header) that it is meant for my particular cloud files container?

It seems to have something to do with DNS, since if I just put "blah.example.com" in my hosts file with the IP address that biglongjibberstring.r89.cf2.rackcdn.com. resolves to - that does not work (gives an error about Invalid URL - appears to be coming from Akamai). The only way I could possibly see this working is if somehow the DNS lookup for whatever.mydomain.com was somehow transmitting back to Rackspace/Akamai DNS servers this relationship between "whatever.mydomain.com" and "biglongjibberstring.r89.cf2.rackcdn.com.". But I've never seen this approach and I don't even think that DNS lookup that goes back to Rackspace/Akamai actually contains the information necessary for this (although I could be wrong about that).

Does anyone know what kind of black magic is going on here?