Questions relating to Networking Files & PPP

[Foung Vang <foung vang esstech com>]

First off, I'll like to say that I was able to get PPP to work just fine.
Now, I'm more interested in how things work and what each networking files
does or jobs are.

Here's what I did to get PPP to work.  My ISP is EarthLink.
1. Start X-Windows
2. Goto Control Panel->Networking Configuration
3. under tab "Names" I enter the following IP address under "Nameservers"
192.168.1.100 <-I have a NetGear Card and assign it this IPaddress
207.217.XXX.XXX
207.217.XXX.XXX
207.217.XXX.XXX
4. Ithen chose to add a new interface, PPP and fill in the informations
requested.  I did NOT chose to use PAP, although it doesn't seem like it
matters.  I was able to access the internet with or without PAP.  Is this
right?
5. Save & run "ifup ppp0" in a terminal and modem begins to dial and
BINGO!!!  Net Access!

Now here's my questions:
1. Is there a way you can tell if your ISP is using PAP or CHAP without
asking them?  I try using Minicom to dial my ISP, and get a login and
password prompt.  After verifying my login and password, a bunch of garbage
shows up telling me that PPP is initiating.  Is this a sign of PAP being
use?
2. What's the difference between HOSTNAME, hosts, lmhosts, & host.conf?
3. When setting up up PPP, do I have to tell it to search "earthlink.net" as
one of the domains?  It seems to work without it, but just curious.  Or is
it only for LAN?
4. host.conf has 
order hosts,bind
multi on
Can somebody explain to me what this is and means?
5. resolv.conf has the list of domains and nameservers to search for
Here's what my looks like
search software
nameservers 207.217.XXX.XXX
nmaeservers 207.217.XXX.XXX
nmaeservers 207.217.XXX.XXX
Do I need to add earthlink.net to the search to make it look like
search software earthlink.net
???

Thanks for any help you can provide me!