On 2018/06/10 13:20, Il Ka wrote:
> Another approach is to extend subnet by decreasing mask to include router to
> client subnet.
> I.e.: 10.112.38.73/16.
I think that's the wrong approach, because it will send packets directly
to addresses which should be sent to the router.
> From my point of view dhcp server in your example violates RFC, it is
> misconfigured
> and should not work at all.
Which RFC? All I see relating to this is "The router option specifies a
list of IP addresses for routers on the client's subnet. Routers SHOULD
be listed in order of preference" which doesn't go into details about
allowed addresses.
We already deal with this for the case fairly common in VPS where the
client gets a /32 with a router outside the subnet (which is a good
thing, it means they can use a vlan per client without using 2x or 4x
the number of addresses). The DHCP RFCs are so old they didn't really
have reason to give much thought to conserving IP addresses.
On 2018/06/10 16:01, Il Ka wrote:
> I just checked how openbsd dhcpd handles this:
>
> subnet 10.10.10.0 netmask 255.255.255.0 {
> option routers 20.10.10.1;
>
> range 10.10.10.10 10.10.10.50;
> }
>
> It starts fine and happily sends unusable configuration to client.
>
> dhcpcd (dhcp client I use on linux-based client) installed funny routes:
> 0.0.0.0 -- 20.10.10.1
> 20.10.10.1 -- 0.0.0.0
>
> So, Internet connection does not work.
The route entries are bound to be a bit funny with this.
How did you configure the rest of networking on the router to cope
with this setup?
