[LARTC] [ard: 2.4routing-howto bugs(1) comments(3)]

[Ard van Breemen <ard@telegraafnet.nl>]

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Hi,
Just like Stegan earlier in this list, I wanted to report the same bug.
I am not sure if it has changed already.
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To: HOWTO@ds9a.nl
Subject: 2.4routing-howto bugs(1) comments(3)
Date: Mon, 28 Jan 2002 14:42:28 +0100
Message-ID: <20020128134228.GC27395@telegraafnet.nl>

Hi,
I have some remarks about the document:
------------------------------------------------------------------------
/proc/sys/net/ipv4/conf/DEV/proxy_arp

Original text:
    If you set this to 1, all other interfaces will respond to arp queries
    destined for addresses on this interface. Can be very useful when
    building 'ip pseudo bridges'. Do take care that your netmasks are
    very correct before enabling this!

Should be:
If you set this to 1, the interface will respond to arp queries on that
interface for destinations of which it knows how to route to other
interfaces.
(I have to check routing back to the same interface, but for that I have
to disable some redirect stuff etc...)

------------------------------------------------------------------------
Another comment on rp_filter:
If rp_filter is turned on, the interface will not even respond to arp
queries if the arp request does not pass the rp_filter! This is very
important for if you are trying to see if a host is responding with
arping.
About every commercial unix system will always reply, no matter what
the requestors ip (of course on the same interface, that is plain rfc),
but linux won't due to filtering.

------------------------------------------------------------------------
Comment on source routing:
As I understood, source routing is routing with hops defined in
the ip packet, in other words: the source defines the route for the
packet. Unless I am incorrect, please use the phrase source address
routing, or routing on source address.
------------------------------------------------------------------------
A comment on the ip stack at all:
You can bind an interface to the kernel ip stack by giving it any
ip address. It really does not matter what this ip address is, since
the ip address will be visible on all interfaces. Just to make it clear:
you can give an interface the ip address 127.0.0.1/32.
After that, you can set up routing to the interface, and just to make
things right: set the default src address for that route to something
sane, and it all works well.
ip route is your friend, netstat -r or route  is not.
------------------------------------------------------------------------
Great howto btw...
I will look for any other things that are incorrect, but the proxy_arp
is the only thing I can currently see.
-- 
<ard@telegraafnet.nl> Telegraaf Elektronische Media  http://wwwijzer.nl
http://leerquoten.monster.org/ http://www.faqs.org/rfcs/rfc1855.html 
Let your government know you value your freedom. Sign the petition:
http://petition.eurolinux.org/