Subnet problems resolved

[Steve Feldman]

I finally figured out yesterday what was causing our problems booting
diskless clients on a subnetted network.

Our servers are running kernels configured with Sunlink X.25.  It turns
out that the installation procedure for version 5.0 of Sunlink X.25
overwrites /sys/OBJ/ip_input.o with an old version that does not
understand how to decode broadcast addresses on subnets.  The more recent
5.2 release specifically avoids overwriting ip_input.o for SunOS 3.4 and
3.5.

Anyway, I restored the vanilla 3.5 ip_input.o and rebuilt the kernels, and
now everything works (except /usr/etc/ping).

Some other things to watch out for:

- If you have multiple network interfaces on a machine, only set the
subnet mask on the first interface or it won't want to talk to any of
them.

- The routing daemon seems to get very confused if you have a
point-to-point link as a subnet and a non-subnetted Ethernet on a gateway
machine.  The only ways I saw to get around this were to make the
point-to-point link it's own class C network or to make the Ethernet a
subnet also.

- We run Yellow Pages.  Getting the host table changes propogated in the
right order so machines could still talk to each other was an adventure.

I'm going to write up some instructions on how to convert to subnets for
other groups in the company.  If anyone wants a copy, let me know and I'll
send you one when it's done.

	Steve Feldman
	oliveb!tymix!feldman at sun.com (internet)
	..!sun!oliveb!tymix!feldman (uucp)
	feldman at tymnet.com (someday)