Router discovery fails on startup

[Chuck R. Anderson]

On Wed, Apr 13, 2005 at 01:03:21PM +0200, Roger Grosswiler wrote:

> This is strange, as if i do /sbin/route i still get my default
> gateway. What EXACTLY is this router discovery for? Ah, btw. perhaps
> it is working because i distribute ip-adresses via dhcp and i
> deliver a default gateway with. Gonna test this evening with a fixed
> ip.

rdisc is an antiquated way for a host to discover the IP address of
its default gateway router before things like BOOTP and DHCP existed. 
It uses a special ICMP request broadcast on the local subnet, to which
a router which is running a router discovery service responds. 
Honestly, I don't know why it was added to the distro.  Perhaps some
RHEL customer requested it.  IMO, it should go to that big bit bucket
in the sky where NCPFS and IPX have gone.

On the other hand, IPv6 has brought back the concept of router
discovery with the radvd daemon.  It uses neighbor discovery protocol
messages (equivalent to IPv4's ARP), though, not ICMPv6.