Subject: Re: /proc/sys/net/ipv[46]/conf/ issue unsolved

From: Hasso Tepper <[email-masked]>
Date: Tue, 13 Feb 2007 22:29:57 +0200

Neil Horman wrote:
> 5) the ifup $DEVICE from (4) goes through the network interface bring up
> process, and consequently sends the ioctl SIOCSIFFLAGS to the kernel, setting
> the IFF_UP flag on the appropriate interface, kicking of whatever default
> processes need to be as defined by the settings found in
> /proc/sys/net/conf/<interface>/*

... which is created _only_ if address of specific address familiy exists
already. If address is obtained via IPv6 autoconf (very common case for
IPv6 hosts) or via IPv4/IPv6 DHCP with netlink aware mechanism (also very
common nowadays - network manager) you don't have any addresses on interface
at this point therefore /proc/sys/net/ipv[46]/conf/<interface>/ are NOT
created. That's the point - you can't configure anything before the first
"carrier up" event - ie. cable is plugged on.

regards,

-- 
Hasso Tepper
Elion Enterprises Ltd. [AS3249]
IP & Data Networking Expert