Subject: [netatalk-admins] Massive dropped connections - any ideas?

From: "Kevin Myer" <[email-masked]>
Date: Wed, 21 Apr 1999 09:07:40 -0400 (EDT)

Hi,

Awhile back, I had written that I was having problems with keeping
Appletalk connections alive on a netatalk box.  Suggestions were made that
the problem was the ethernet card, client operating system or client
etherent card.  However, none of these seem to make sense and as I am
hoping to move all our AppleShare stuff to a netatalk box, I really need
to figure out what is causing this.

First, the hardware:

Originally, I was running this off of my own workstation, a homemade box
with an AMD K6-2 300Mhz processor, 128Mb of RAM and a 3com 905b ethernet
card.  I was running kernels 2.1.x up through 2.2.1.

Thinking it might be the ethernet card or machine, I switched the service
to a box with dual Pentium II's running at 300Mhz with 512Mb of RAM and
currently running kernel 2.2.3.  The card is an Intel EtherPro 100+.

Now the problem:

On both machines, connections are randomly dropped.  In some cases, there
is massive connection dropping, i.e. a whole lab goes offline at the same
time.  In some cases, its just a matter of having a teacher log into the
volumes again.  In other cases, the server won't respond to Appletalk
requests, although Appleshare IP requests work ok.  In even other cases,
the server won't respond at all.  In the latter case, for whatever reason,
all the netatalk related daemons have died (a good reason its not
responding) but there's no clue in the logs as to why they died - just a
slew of dropped connections and then silence.

I have read reports that both of the ethernet cards I am using are
troublesome when it comes to multicasting.  I am not sure if that is my
problem or not.  I do have the Intel card compiled with
multicast_filter_limit=3, which is supposed to take care of that problem
and I am using the latest ethernet card drivers.

I've read on these lists that people expereinced some Appletalk problems
after upgrading to the 2.2.x kernel series and I noticed in the latest
kernel release that there are Appletalk updates.  However, I need to wait
for a set of RAID patches against the 2.2.6 kernel before upgrading the
server to see if that makes a difference.

I believe I can effectively rule out the clients as the problem, as they
all have six Appleshare volumes mounted off a Windows NT server that never
go down.  Although it wouldn't suprise me that NT does something not right
to keep the connections alive, I have to assume that those connections are
working properly and its the netatalk/Linux/ethernet card combo that is
giving me trouble.

This is really troublesome to try and justify to the librarians and
supervisors that Linux is a good path to take, when stacked side by side
with NT (at least for the Services for Macs part), NT is far more stable.

I'm hoping someone can offer a suggestion to point me in the right
direction, or confirm a kernel or netatalk bug, or at least say "Yes,
I'm having that problem too".  

If I haven't provided enough useful information, ask.  I'll be glad to
supply it.

Thanks,

Kevin

-- 
     ~        Kevin M. Myer
    . .       Network/System Administrator
    /V\       ELANCO School District
   // \
  /(   )\
   ^`~'^

---

From: Christof Warlich <[email-masked]>
Date: Wed, 21 Apr 1999 22:32:08 +0200

Hi Kevin,

I really appreciated reading your posting, because it at least gave me
hope
back that I´m not the only one in the world having exactely the same
problem.
It´s just 2 weeks ago when I posted this to [email-masked]:

Christof Warlich wrote:
> Hi all,
>
> I´ve recently upgraded my aged netatalk1.4b2 installation to
> netatalk1.4b2+asun2.13,
> and data transfer rates became fantastic compared to the old
> installation.
> But unfortunately, every some 10 minutes the Macs are loosing the
> connection
> to the server, which is a Linux box with a 3COM590 and kernel 2.036.
> Anyone out
> there who had the same problem and found a solution?
>
> Just because I´ve started to ask: I already tried to subscribe to the
> LINUX-ATALK
> list several times by sending a mail to [email-masked] with no
> subject and a
> body which reads "SUBSCRIBE LINUX-ATALK", but I never got any response.
> What´s wrong?
>
> Thanks for any help, especially on the first problem.
>
> Christof

I got the following two responses (Thanks for the help, Jonathan and
Brad):

Jonathan Benson wrote:

> I suspect your card may be the problem.  Check anything in the drivers to do
> with multicast.
>
> The best cards for use with netatalk seem to be those based on the Tulip
> chipset.
>
> Take a look at:
> http://cesdis.gsfc.nasa.gov/linux/drivers/tulip.html
>
> Regards
>
> Jonathan
>
> --
> Jonathan Benson B.Eng. (Soft Sys Hon) <[email-masked]>
> Systems Administrator, Phoenix Magazines, Phone: +61 3 9696 7200
> http://www.phoenixmags.com.au/

Brad Cox wrote:
> Deleting any mac-style aliases on the mounted volume worked for me.
>
> Use unix ln -s instead.
>
> ---
> Dr. Brad Cox [email-masked] (update your address book)
> Phone: 703 361 4751 Fax: 703 995 0422 Cellular: 703 919-9623
> http://virtualschool.edu/mon A Project with Paradoxical Goals
> PGP Signature: E194 C6E5 92D8 B8FB 20E8  8667 929A 95A0 FCB6 7C62

I´m currently planning to give Jonathans suggestion a try, though I will 
need another two month to really do it, because the machine in question
is at the printing office of my brother, 500km away from my home, and it
will take that long to be able to visit him again. Anyway, I´ll give a
report 
on whatever I´ll experience then, at this list and to your email
address. 
If you get any new information, please let me know. 

Concerning the second part of my posting: You apparently have subsribed
to LINUX-ATALK, do you know why I can´t?

in thr hope that we get the porblem fixed,

Christof

---

From: Jonathan Benson <[email-masked]>
Date: Thu, 22 Apr 1999 10:19:42 +1000

> with NT (at least for the Services for Macs part), NT is far more stable.

As I think I already told you.  Change the network card!!

I had the SAME sorts of problems with an Intel card.  From what I've seen here
since you might be able to get it working by fiddling with some setting to do
with multicast support, but if you've got the money, just get a Tulip based
card and avoid all the hassles.

The multicast support on the Intel and 3Com cards is crap compared to that on
the Tulip based boards.

See:

If you don't want to spend the money on one of these cards then at least try a
cheap NE2000 clone.  I was running an ISA NE2000 clone for a while to prove
that the problem was the Intel card that had been in the box and it worked
perfectly (except for the obvious limitations of a cheap ISA NIC).

Regards

Jonathan

---

From: Keith Clarke <[email-masked]>
Date: Mon, 26 Apr 1999 14:56:27 +0100

>The multicast support on the Intel and 3Com cards is crap compared to that on
...
>Jonathan

And yet UAR works with these cards tho' atalkd does not...

We have two file servers - Netatalk 1.4b2 running under FreeBSD 2.2.6, and
Netatalk1.4b2+asun2.1.0 running under FreeBSD 2.2.8. We want to make these
services available to another subnet connected via a software router, and
thought to use atalkd for the DDP routing (atalkd from
Netatalk1.4b2+asun2.1.3).

Simon Boggis of our Dept just posted the following to the list
<mailto:[email-masked]> -

>I have been trying to set up appletalk routing only (no file serving) on a
>linux router box which is equipped with 3 dual port eepro100+ (82558B)
>cards. The system is linux 2.2.6/glibc 2.1.1 (Debian Potato), however I am
>using the 1.07 eepro100 drivers (rather than 1.06, as shipped with the 2.2.6
>kernel). I have been attempting to bridge appletalk between our main
>network on
>eth0 and a private subnet on eth3.
>
>Curious things happen when the appletalk module is installed -
>one gets lots of:
>
>Apr 20 18:34:34 MACHINE kernel: protocol 9b80 is buggy, dev eth0
>Apr 20 18:35:20 MACHINE kernel: protocol 0008 is buggy, dev eth0
>Apr 20 18:38:21 MACHINE kernel: protocol 0400 is buggy, dev eth0
>Apr 20 18:40:14 MACHINE kernel: protocol 3781 is buggy, dev eth0
>
>in /var/log/debug if you tcpdump eth0.
>
>When netatalk (atalkd only) gets fired up, appletalk connections hang quite
>quickly, accompanied by messages in /var/log/messages:
>
>Apr 15 17:52:36 MACHINE kernel: eth3: Transmit timed out: status 0050
>0000 at 17015/17030 command 00000000.
>Apr 15 17:52:36 MACHINE kernel: eth3: Trying to restart the transmitter...
>
>There has been a lot of discussion on the netatalk-admins list concerning
>this,
>which I have been following, and the conclusion there was that the hardware
>was broken, but could be worked around by setting multicast_filter_limit=3.
>I have no idea why '3' particularly, however in my case I found the solution:
>
>(a) didn't work (macs still hang after a minute or so) (:
>(b) stopped mrouted from working on the machine
>
>and therefore wasn't much of a solution at all for me.
>
>Having consulted a colleague, I was assured that appletalk works fine on pc
>hardware with eepro100's using Novell Netware. I therefore was suspicious of
>the diagnosis of a hardware fault in the eepro100 offered above.
>
>In order to isolate software from hardware, I tried the much older Univeral
>Appletalk Router (UAR 1.0.16 September 1995) which doesn't use the appletalk
>support in the linux kernel. This works absolutely fine. This leads me to
>believe (perhaps incorrectly) that the hardware and eepro100 driver are fine,
>but that either netatalk and/or kernel appletalk support is broken.
>
>Has anyone else been having trouble with appletalk on the eepro100? More
>importantly, does anyone have a view on whether my above analysis is correct
>(i.e. the hardware and driver are OK).
>
>Simon
>

UAR working "absolutely fine" describes a simple test - a single Quadra620
running OS8.1 on the private subnet, running an AppleScript copying a 30MB
folder (400 or so files) continuously for three days from the
AppleTalk-only server. This test caused a hang within ten minutes using
various different configurations of atalkd as the router.

Are we doing something wrong here (i.e. trying to use atalkd as a router,
with no afpd) ?
We'd be really happy to help out with debug logs etc - just tell us what's
needed. Of course a possibility is that Netware and UAR are accidentally
working round bugs in the card...

thanks
Keith Clarke

---

From: a sun <[email-masked]>
Date: Mon, 26 Apr 1999 12:29:31 -0700 (PDT)

>in /var/log/debug if you tcpdump eth0.

are you sure that this is from a linux 2.2.6 kernel? this is a
cosmetic bug that i fixed in 2.2.6. it only manifests when you stick a
network interface tap of some kind (e.g., tcpdump) on with appletalk
active.

   >Apr 15 17:52:36 MACHINE kernel: eth3: Trying to restart the transmitter...

by definition, this has to be an ethernet card/driver problem. 

   >In order to isolate software from hardware, I tried the much older
   >Univeral Appletalk Router (UAR 1.0.16 September 1995) which
   >doesn't use the appletalk support in the linux kernel. This works
   >absolutely fine. This leads me to believe (perhaps incorrectly)
   >that the hardware and eepro100 driver are fine, but that either
   >netatalk and/or kernel appletalk support is broken.

that's not necessarily true. the eepro100 card has some timing issues
w.r.t. multicast that atalkd has a tendency to aggravate. uar may not
be triggering things in the same way. usually, this turns out not to
be a problem because most people aren't using a many-zoned
network. before ruling out a driver/card problem, i would suggest
trying out a dec tulip card first.

-a
[email-masked]