Le 28/12/2017 à 13:01, Mark Fletcher a écrit :
That means that, if the goal were only to get a working setup, that has
now been achieved. However, if you'll indulge me further, I'm now very
curious about how I can get the AirStation to have a sensible routing
table -- surely it must be possible. Beyond the man pages for DHCPD is
there a good reference anyone can recommend for exactly what happens
when a DHCP request is made?
The authoritative sources are the RFCs. Not the easiest to read though.
However they will only describe what happens on the wire :
client sends DISCOVER.
server sends OFFER.
client sends REQUEST.
server sends ACK.
Client messages contain options that the clients requests. Server
messages contain option values. Now what is done with the option values
is up to the client.
By "not even handle the netmask correctly", do you mean "not even
properly infer from a netmask of 255.255.255.0 and IP address of
192.168.1.2 that it should be able to talk directly to any computer in
192.168.1.0/24, and hence not try to send such connections via its
default gateway"?
Yes.
I'm going to play with static-routes first -- first will have to read up
on the difference between a classful and a classless route...
Classful addressing assumes that the netmask is implicity tied to the
address. E.g. with private ranges :
10.0.0.0 => class A => netmask 255.0.0.0
172.17.0.0 => class B => netmask 255.255.0.0
192.168.1.0 => class C => netmask 255.255.255.0
Classless addressing does not assume any implicit relation between the
address and the netmask, so the netmask must always be explicit.
Since 192.168.1.0 is class C, the classful netmask matches the actual
netmask, so it's fine to use static-routes for this subnet.
I noticed the connection attempt to the PI arriving first at the
firewall, then the firewall sending the AirStation an ICMP redirect.
As expected. But the Airstation behaves as a router, and IIRC a router
may ignore ICMP redirect. Even though, an ICMP redirect can be accepted
only when the suggested address is directly reachable. At the moment,
this is not the case otherwise the Airstation would not have sent the
original packet to the firewall.
So the remainder of the issue becomes, how does one persuade a Buffalo
AirStation to properly set its routing table on its WAN side after
receiving an IP Address by DHCP? I'll read up about the static-routes
next -- got nothing to lose by trying it.
I do not remember if it has been mentioned, but doesn't the Airstation
support static IP configuration on its WAN interface ?
