On 10/19/2015 02:14 PM, Martin Pieuchot wrote:
On 19/10/15(Mon) 13:37, Gregory Edigarov wrote:
On 10/19/2015 01:24 PM, Stuart Henderson wrote:
On 2015-10-19, Gregory Edigarov <ediga...@qarea.com> wrote:
In order to conserve address space I am trying to confugure 'ip
unnumbred' in cisco terminology, that is have an interface borrow the ip
of a different interface, I am experimenting with vether0 and vlans the
thing is to have one 'main' address on some 'real' interface and then
just add routes pointing to the right interfaces.

# ifconfig vether0 192.168.100.1/24 up
# ifconfig vlan2 vlandev vether0 up
# ifconfig vlan3 vlandev vether0 up
# route add 192.168.100.2/32 192.168.100.1 -cloning -ifp vlan2
route: writing to routing socket: Network is unreachable
add host 192.168.100.2/32: gateway 192.168.100.1: Network is unreachable

the same result I have if I am trying to configure this on a real
interface connected  to my network:

# ifconfig vlan2 vlandev re0
# ifconfig vlan3 vlandev re0
# ifconfig re0 alias 192.168.100.1
# route add 192.168.100.2/32 192.168.100.1 -cloning -ifp vlan2
route: writing to routing socket: Network is unreachable
add host 192.168.100.2/32: gateway 192.168.100.1: Network is unreachable

# uname -a
OpenBSD lbld12.duckdns.org 5.8 GENERIC.MP#1507 amd64

I thoght OpenBSD supports such thing.

am I missing something?
I don't *think* this is expected to work at the moment unless possibly
you specify a destination MAC address with -link.

It does work with point-to-point interfaces, e.g. you can have
192.0.2.1/28 on em0 and 192.0.2.1/32 on pppoe0 and things will work
as expected, but in that case you don't have a problem of picking a
particular link-layer address, just "the pppoe0 interface" is enough
information for the system to know where to send the packet.

The best I've done so far for address conservation on ethernet-like
interfaces is to use /31's (which works well).

Yes, I know /31 would work correctly, but I wanted further space
conservation.
Does it?

Is that a correct explanation that this does not work because  our routing
table still wants a link layer address, errrmmm,  arp table is  included in
routing table?
I believe it's simpler than that.  You cannot attach a route to an
interface without address, so I'm quite sure it will work if you add
an address to vlan2.
yes, adding a route works now. thanks, Martin. will test some further later.

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