Internet Extender for DOS and ODI drivers

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Luis A. Loeff

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Dec 22, 2001, 5:05:57 PM12/22/01
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Hi Folks

I have been experimenting with a NAT program that runs in DOS
between a LAN and the Internet.
In order to run the program (Internet Extender) I first load
the packet drivers corresponding to the NIC's or the modem and NIC
that are used.
The program runs fine when packet drivers are used but if I attemp to
use ODI drivers (LSL.COM + 2 ODI drivers + 2 odipkt (or pkt2odi)) then
it will not work and most likely freeze the computer.

However other DOS internet applications will run fine with either NIC
even both ODI drivers are loaded.

Regards

Luis A. Loeff

Jan Just Keijser

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Jan 3, 2002, 7:03:16 AM1/3/02
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how are you loading the odi & odipkt drivers - odipkt.com is VERY sensitive to
the max frame (buffesr) size setting in the net.cfg, IIRC. Look at

http://fog.bio.unipd.it/pub/Networking/Dos/Odipkt/readme21.txt

for example

HTH,

JJK

In article <75be8039.01122...@posting.google.com>, an...@tsp.com.br

---------------------------
JJK / Jan Just Keijser
Unix/Linux Systems Engineer
smtp: jan...@cisco.com

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Dan Lanciani

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Jan 4, 2002, 2:38:23 AM1/4/02
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In article <1010059617.40250@sj-nntpcache-3>, _no_spam_janj...@cisco.com (Jan Just Keijser) writes:

| how are you loading the odi & odipkt drivers - odipkt.com is VERY sensitive to
| the max frame (buffesr) size setting in the net.cfg, IIRC.

Actually, odipkt isn't at all sensitive to the frame size. The frame size is
a function of the network medium. Unfortunately, a number of people who did
not understand LSL buffering published odipkt "howto" guides with incorrect
information about buffer sizes and broken sample net.cfg files. There were
two basic flavors of wrongness. The most wrong versions claimed that the buffer
size should be 1500 on Ethernet. This is always wrong for all versions of LSL.
The more subtly wrong versions claimed that the buffer size should be 1514.
This is wrong for some versions of LSL but right for others since newer versions
of LSL actually took the internal overhead into account. Of course, the guides
never mentioned the required version of LSL so 1514 was in fact nearly as bad
as 1500.

In either wrong case large packets would typically overwrite a few pointers of
the next buffer and cause extremely obscure crashes. People blamed this on
odipkt. Other helpful people came up with still more "howto" guides that
suggested tweaking various packet driver applications so that they wouldn't
use big packets to make up for odipkt's "bugs." It was a vicious circle. :(
A buffer size of 1600 is safe for all versions of LSL on Ethernet. If you
are concerned about wasted memory, check to make sure you aren't allocating
any mempool. The same broken net.cfg samples with the wrong frame size often
included mempool settings that they claimed were needed for odipkt. (Odipkt
does not use any mempool.) Possibly in playing with the configuration someone
had found that allocating mempool moved things around and changed the timing of
the crashes caused by the wrong buffer sizes, hence the rumor that odipkt needed
mempool...

Dan Lanciani
ddl@danlan.*com

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