🚀 go-pugleaf

malcolm@pandanus.ntu.edu.au (Malcolm Caldwell) writes:

>>Internet Routers.  If you have a device in the bridged zone that requires a
>>static IP address, then you are, in technical terms, screwed.  You'll have to
>>move the device over to the directly connected zone.

>But why is this the case?  What is the technical reason.

It relates to the ability of the IP/Appletalk gateway to locate the
Appletalk address that relates to your mac with the static address.

If the mac was to request its address from the gateway, then the gateway
would remember the appletalk address from that request, and all would
be OK.

However, if the address is static, and a packet arrives address to your
mac, then te gateway has to find its appletalk address somehow.  The way
it does that is via an NBP lookup - but that is directed to just one
zone.  All will be OK if both sides of the AIR are in the same zone, as
the lookup will reach your mac, but if they're not, your mac will never
see the lookup, therefore never reply, and so the gateway will have no
idea where to send the packet.

Some gateways will remember your appletalk address if you send them a packet
before one is sent to you, but that's at best an unreliable way to work.

There is work in progress to define a new packet that the IP layer on
any mac with a static address can send to an IP gateway when it (the mac
IP layer) starts, to inform the gateway of the IP address <-> appletalk
address mapping, which will (should) cure these problems - at least for
as long as the gateway stays up, if it crashes then when it reboots it
will have lost the info, but the mac won't know to resend the magic packet.

kre