Re: your mail

Nick Holloway (Nick.Holloway@alfie.demon.co.uk)
12 May 1996 19:06:01 GMT


Alan Cox <alan@cymru.net> wrote:
> Yes. A route is auto added for each device with its netmask. That makes
> various bits of BSD code work that assume this way of working. Unlike BSD
> you can delete these routes trivially if you want to pull something funny.

I haven't seen any reply to Jonathon Kamen's posting in the newgroups,
but I too have had my setup wrecked by this feature.

When the machine first boots, I have the loopback and the dummy device
installed. The dummy device allows me to connect to my IP address
158.152.44.128 when I am not connected. Great.

Kernel routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
127.0.0.1 * 255.255.255.255 UH 0 0 0 lo
158.152.44.128 * 255.255.255.255 UH 0 0 0 dummy
127.0.0.0 * 255.0.0.0 U 0 0 0 lo

However, when I dial up, because the route is added for the ppp device,
I lose the route to the dummy device (even when it is added with a
non-zero metric). Now, when the ppp link is dropped, I lose my route
to my IP address.

I know that I could modify ip-down to add back the route to the dummy
device, but this still leaves a window of no route. This is bad, as
the errors are hard -- 'Network is Unreachable'.

I don't want to have network failures to interrupt my news reading off
my local nntp server just because the link has dropped.

You claimed that this was in search of BSD compatability, but it is
not complete enough -- I know that BSD people do not need to have a
dummy device, they can have an address recognised as local without it
(although I don't know how).

So, my vote is to remove this feature, or at least make it a config
option.

-- 
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