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From Michael Douglass <>
Subject Re: [Fwd: WARNING - Solaris 2.5 bug - slow Web serving]
Date Fri, 28 Jun 1996 20:38:35 GMT
On Fri, 28 Jun 1996, Rob Hartill wrote:

Ok, this is a known bug in 2.4 (after installation of a patch), 2.5, and
2.5.1.  Sun has fixed the problem and a patch is supposed to be coming out.
I have been watching for the patch like a hawk; but here is a workaround
to get you almost completely normal bandwidth down those modems that your
users are using:

ndd -set /dev/tcp tcp_rexmit_interval_min 800
/usr/sbin/ifconfig le0 mtu 512

Both of these items together bring you back to almost normal speed.  The
problem was in Sun's revised retransmit algorithm that worked wonderful on
10 megabit.. but not on modems....  The above "fixes"/"work arounds" cause
the retransmissions to be set at a longer time frame, and the mtu forces
the packets to smaller sizes to allow for quicker returns on ACKs (and
smaller retransmissions if a packet has to be retransmitted).

The Solaris 2 faq tells you to do the first line (ndd -set) with 3000; but
to me 3 seconds is quite a while to have to wait if you honestly drop a
packet.  So I took the middle road and did the above.  It works quite well
as I have a web server, a mail server, and a news server off of three
seperate 2.5 boxes.

Michael Douglass
Texas Networking, Inc.

  "To be a saint is to be an exception; to be a true man is the rule.
   Err, fail, sin if you must, but be upright.  To sin as little as
   possible is the law for men; to sin not at all is a dream for angels."

              - Victor Hugo, "Les Miserables"

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