Map APPC LU name to an internet address

Once again pardon my ignorance of the as400.
I am trying to configure AnyNet/400 APPC over TCP/IP.  And step 5 is "Map
APPC LU name to an internet address".  The details include adding entries to
the host file.  First off I do not like hosts files and have a dns and have
the as400 pointing to the dns.  (1st question) Do I need to do this step?
Especially if I have the dns server.
(2nd question) the following is what the "howto" has for info and what I
need in the host file

* RALYAS4B - remote SNA location (LU) name
* USIBMRA - remote SNA network ID
* SNA.IBM.COM - SNA Domain Name Suffix

I understand the first line as the as400's hostname.  Ours is something like
"s10xxxxx".  However the "SNA network ID" is throwing me for a loop.  Where
would I find that info?  Then the "SNA domain name suffix" - where is that
found or configured?  Or this just an example like the rest and it could
just be "foo.bar"?

Thanks for the help,
Doug