[NCLUG] Routing confusion

dobbster dobbster at dobbster.com
Mon Oct 28 19:31:48 MST 2002

Hi all,

I've been on a bit of an adventure lately which has eaten away lots of
hours.  I'm back above water again, but I'd be grateful for any future
advice on any of this stuff!

It all started when I acquired a nifty RH348 NetGear external ISDN
router (Thanks, Sean!) and attempted to configure it.  I didn't know
the password, so I had to download a flash upgrade to the thing.

The router required XMODEM to receive the upgrade.  For some reason,
minicom kept failing.  I eventually and reluctantly tried it with
hyperterm and it worked (any idea why this would be?)

(Over)confident that I had the router working, I proceded to change
the network configurations on both of the machines which were on the
network.  Previously, I had been using IP Masqurading, which worked,
but was slow.

Foolishly, I didn't record any of the previous settings...    Then I
discovered that the router wouldn't load its configuration menu; it
hung before getting to the password prompt.  I still don't know what's
going on with that.  But since these machines are pretty critical to
our business, I had to back up and go back to the IP MASQ

I had no idea what I did along the way, but I couldn't restore things
to their original state.  First pppd died.  I amended this by patching
a 'route del' command into /etc/rc.d/rc.local to remove the default
gateway, which was an internal IP for the system's ethernet card

Then I had to similarly add a 'route add' to /etc/rc.d/rc.local on the
other machine to get it to connect to the Internet.

I spent a lot of hours fooling around with this...  I've read
documentation, but I am still confused about how the routing tables
put themselves together.  It seems that putting these commands into
rc.local is a poor way of doing things.  So I wonder:

- How do the various files /etc/sysconfig/* affect the routing table
the machine starts up with?  How am I *supposed* to change default
gateways, etc.?  I know that the tables are kept in the kernel, but
how do they load?

- Is hacking /etc/rc.d/rc.local an acceptable solution?

- I am using ipchains in the IP MASQ setup because of the older kernel
version.  Does this make any difference?

- (I've looked, but had trouble finding answers to this...)  If/when I
get the ISDN box to talk to me, how should I configure the routing
tables on the machines within the intranet (

I know these are naive and perhaps vague questions.  Unfortunately,
everything I set up works so perfectly for so long (Uh-huh :-) that a
year or two later, I forget what the heck I was doing.   I hope I'm
not the only one who suffers from information overload...

Ah well, thanks,

Mark Story
dobbster at dobbster.com

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