Fwd: gateway updates

Bill V WA7NWP wa7nwp at gmail.com
Mon Feb 1 11:11:41 PST 2010

FYI - update on Brian's work from the 44Net list.   It all sounds good
and hopefully they will remove the requirement for a static/commerical
IP for participation.

Bill - WA7NWP

---------- Forwarded message ----------
From: Brian
Date: Mon, Feb 1, 2010 at 10:59 AM
Subject: Re: [44Net] gateway updates
To: 44Net at cows.net

For future:

Work on integrating OpenVPN is progressing.  That would allow gateways
to dynamically 'log in' to AMPRGW; that login would update the routing

AMPRGW is already sending RIP notifications to all known gateways; these
contain its current view of the subnet connectivity.  By using the information
in these notifications to update a routing table, any gateway can have
information as to the current address of the gateway to each subnet.

I have in mind to send ICMP Redirects from AMPRGW.  If this works, a host
sending from the great unwashed internet to an AMPRNET address would
send its first
packet to AMPRGW (which would forward it), but would also receive an
ICMP Redirect
informing that the more direct gateway to that host is located at address <x>,
and that it should send further traffic for that host to there.

Note: icmp redirects are expected to expire, typically after a few minutes, so
if a gateway DOES move from one commercial address to another, it'll only be
unreachable for those few minutes.

Note: If a host ignores the redirect and keeps sending its traffic
through AMPRGW,
no harm done.  Redirects will NOT be sent for each inbound packet; I expect to
implement some sort of backoff so that a host ignoring them won't get pummeled
and the network won't get congested, but there should be enough that
the occasional
dropped ICMP packet won't cause problems either.

Note: this allows there to be more than one AMPRGW.

I've not found a way to do proxy BGP, so ICMP redirects are the best I can do
so far.  More and better ideas are certainly welcome.
       - Brian

On Mon, Feb 01, 2010 at 11:34:55AM -0700, Jim N7VR wrote:
> You are correct, Barry.
> The Email files and the FTP site are only updated once per day at 00:01 GMT. It takes a few minutes to have all the files sent out.
> An updated encap.txt file is sent to amprgw at UCSD at the time an entry is added or updated.
> Two points.
> First, the requirement for a static IP has not been dropped. Therefore, we should not have quick changes in systems.
> Secondly, to implement a system that can handle this would require
> all gateway operators to update based on a sent file, similar to what
> Brian does. In the past, requests for this have not been successful. Some
> still want to ftp their file rather than accept a pushed out file. The
> load on my system, during peaks, could be greater than I wish to have
> with the combination.
> Jim Fuller

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