Subject: [netatalk-admins] Routing in the chain of the linux servers...

From: Konstantin Reznitsky <[email-masked]>
Date: Fri, 9 Jul 1999 10:39:28 -0400 (EWT)

I wrote this a while ago and sent it to umich support people, never got
anything back. It is written in their "BUG REPORT" style. 

Environment:
        Two Pentium (233/200MHz) machines running Red Hat-6.0 and
        netatalk-1.4b2+asun2.0a18.2-oa1 (I tried your 1.4b2 without asun
        with the same success) connected like this:

                      ------               ------
        WS1       eth1|    |eth0  WS2  eth1|    |eth0       WS3
        --------------| L1 |---------------| L2 |-----------------
        Zone1         |    |    Zone2      |    |           Zone3
        net(range)1   |----|  net(range)2  |----|       net(range)3

        L(1,2) are linux based routers.
        WS(1,2,3) are test Macs with classic appletalk or open
        transport (doesn't matter).

Description:
        The problem is in when who can see whom, depending on which Zones
        the routers belong to; file shares on L1 and L2 are seen by all
	WSs in 	any configuration below. So are all the zones. "See" means
	show in the chooser and can connect to the shared volumes."->"
	means default zone for the router.

        1. L1->Zone2 and L2->any zone(2or3) - all WS(1,2,3) can see each
        other.

        2. L1->Zone1 and L2->any zone(2or3) - WS2 can see WS1 and WS3,
        WS1 can see WS2 and WS3, but WS3 can see only WS2 and NOT WS1.!!!

        I have a strong feeling that this happens because the default zone
        on the router L1 is configured on the second (eth1) interface,
        unfortunetly I could not test the oposite because of the hardware
        restrictions - different type of media (I do not have one more
	hub). L1 machine has 3c905 and PCI NE2000 (Realtech), 3Com always
	wants to be the first (eth0) and doesn't have a BNC connector.

        I experimented with UAR (from CAP people) this effect never showed
	up.
        So, another thought, it might have something to do with appletalk
        implementation in the kernel (UAR is not using it). Kernel 2.2.5 -
        standard with RH-6.0. Tried RH-5.2 with 2.0.36 on the L1 with the
	same effect.

Fix:
        Assign the default zone on L1 to the network that connects it to
	L2.

        But here is another question. Is there a way to use this bug (or
        whatever it is) to hide computers on one of the networks. It could
	be very useful for example to connect this way admistration's and
	students' networks. The question is how reliable this configuration would
	be? This is another promlem, I was dealing with. Is there a way to
	hide certain networks (zones) on the network intentionally? As far as I
	know only certain hardware routers can do it. Is there any way to do it
	with atalkd?

Thanks for any advice....

Konstantin.

---

From: Patrik Schindler <[email-masked]>
Date: Fri, 9 Jul 1999 18:19:28 +0200

>        WS1 can see WS2 and WS3, but WS3 can see only WS2 and NOT WS1.!!!

I had a similar setup here, all the same zone name. I saw WS1 from WS3 and vice versa. But connecting to each other failed "No answer from server"; Adrian said, this is a bug in the kernel code which should be fixed in 2.2.10, but darkly remember that I read this of 2.0.36, too. 2.0.36 has the bug.

>	students' networks.

This is a BUG and I'd never build anything on a bug.

:wq! PoC