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From: jqj@duff.uoregon.edu (JQ Johnson)
Newsgroups: comp.sys.mac.comm,comp.protocols.tcp-ip
Subject: MacTCP routing question
Message-ID: <1991Jun7.191614.17253@ns.uoregon.edu>
Date: 7 Jun 91 19:16:14 GMT
Sender: news@ns.uoregon.edu
Organization: University of Oregon Network Services
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Can anyone familiar with the internals of MacTCP explain how MacTCP
routing works?  From the MacTCP Programmer's Guide I conclude that for
Ethernet-connected Macs it "supports" RIP and a default route that can be
statically configured (in the obvious place in the CDEV).  My question is
"what does 'supports' really mean?"

How much of RIP does MacTCP support?  Is it like the braindead Kboxes that
look only at the size and source IP address of the RIP packet, or is it
more like Unix "routed -q"?

From the MacTCP Administrator's Guide, one gets the impression that the
implementation is even worse than that in a Fastpath, and that MacTCP
might simply use as its current default gateway the address of the host
from which it has most recently received a RIP packet of any form.

Does MacTCP maintain a full routing table similar to the one used by BSD
with host/network/default and RIP-derived/static/ICMP-derived route
distinctions?  Assuming that MacTCP has been told a correct subnet mask
(by static configuration or by bootp data), does MacTCP correctly store
subnet routes?  Does MacTCP even pay attention to ICMP redirects (I assume
yes since MacTCP doesn't report them to the application along with other
ICMP messages), and if so does it time them out?

I assume that MacTCP maintains a traditional ARP cache.  Does it time out
ARP entries?

Since being a RIP listener requires that one process IP broadcasts, what
broadcast addresses does MacTCP pay attention to?  Presumably the local
broadcast address, {-1,-1,-1}.  How about the network broadcast address
{net,-1,-1} and the subnet broadcast address {net,sub,-1}?  How about
old-style 0-filled "broadcast" addresses?

Do the answers to any of the above questions depend on whether it's the
current MacTCP 1.0[12] or the new version expected to be released in a
month or so? 

-- 
JQ Johnson
Director of Network Services		Internet: jqj@oregon.uoregon.edu
University of Oregon			voice:	(503) 346-1746
250E Computing Center			BITNET: jqj@oregon
Eugene, OR  97403-1212			fax: (503) 346-4397