[comp.protocols.tcp-ip] plea for help

AFDDN.TCP-IP@GUNTER-ADAM.AF.MIL (09/16/89)

   I've been around the internet for some time now, and routinely read this
list.  I now find that I must become a lot more knowledgeable about the
workings of certain interfaces (luckily all based on unix to some degree).
I must become the host admin and general techie for three machines we 
recently obtained.
1) Sun 386i
2) DEC uVAX II w/ Ultrix 2.2
3) AT&T 3B2-600G w/ UNIX (but not BSD)

  The Sun has an ethernet inreface.  The uVAX has a DELQA ethernet interface
and an ACC 5250 X.25 card.  The AT&T has an ethernet interface and an ACC
X.25 card.  The AT&T is running TWG's WIN3B package.  I have several naive
questions about unix and connecting networks.

  On the DEC and the AT&T there are three files in /etc.  I roughly 
understand the files as follows.  hosts has host names and IP addresses for all
the hosts which you enter.  This table can be updated from hosts.txt, or so
I assume.  networks contains the names and net numbers of all the networks, 
which is also in hosts.txt.  Last there's gateways, which contains the 
network, gateway address, netmask, broadcast address and metric for all the
networks.  I understand there's a problem in building the gateways file
from hosts.txt, although I don't know the details.  

  For all the systems, the hardware is configured with an IP address and 
brought up using ifconfig.  For the the AT&T, inetinit brings up the 
internet software and reads inetinit.cf.  On the uVAX, inetd reads inet.conf
to get things going.  That's about the limit of what I know and some of it
may be wrong.

  Some first questions are:  Can each hw interface only have one IP address
given in the ifconfig??
What are the relationships between networks, gateways, hosts, and the IP 
addresses given in ifconfigs??
What is the difference between using "route add" and editing the gateways file?
Are there any well known bugs with any of the three interfaces I should
be concerned about (considering my current limited experience)??
Any help or pointers would be apprciated.
Please send directly to me so as not to flood this list with stuff 
most other readers might know.
Darrel B.
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