Skip site navigation (1)Skip section navigation (2)
Date:      Thu, 16 Nov 2000 06:49:54 -0800
From:      "Jeremiah Gowdy" <jgowdy@home.com>
To:        "sanjeev singh" <remraf@hobbiton.org>, <freebsd-questions@FreeBSD.ORG>
Subject:   Re: natd limiting download speed?
Message-ID:  <00b701c04fdc$7b1afea0$aa240018@cx443070b>
References:  <Pine.BSO.4.21.0011141717490.22743-100000@thorin>

next in thread | previous in thread | raw e-mail | index | archive | help

----- Original Message -----
From: "sanjeev singh" <remraf@hobbiton.org>
To: <freebsd-questions@FreeBSD.ORG>
Sent: Tuesday, November 14, 2000 3:20 PM
Subject: natd limiting download speed?


>
>  Hello,
>
>  I recently set up an ipfw+natd machine (FreeBSD 3.5.1R) for sharing my =
>  cable connection.  Unfortunately, natd appears to be limiting the =
>  maximum bandwidth available!
>
>  Using netperf, I have established that I can get up to just under 4mbps =
>  with natd enabled, and 4.3mbps with it disabled.  This might not look =
>  like a big deal, except that in the former case, my CPU is fully loaded =
>  whereas in the latter it's only at 50%!
>
>  Also, when testing high speed downloads (from netscape.com), I get the =
>  following results:
>  Download speed: ~350+KB/s
>  CPU States: 50-60% system, ~35% interrupt and <10% idle
>  natd takes up 80% of WCPU and CPU
>
>  My firewall machine is a 486/66 (32MB Ram) with an NE2K and a Dec DE =
>  201.  Are these results in the ballpark or could I have configured =
>  something wrong?

Using a 486 66 with 32megs I can't see what the problem is.  Of course
you're going to lose speed to such a slow computer.  May I suggest you order
a newer computer, even something as simple as an AMD K6-2 500mhz with
motherboard can be purchased from PriceWatch.com for $109.

If you're using anything less than a Pentium Pro or K6, I would expect lag
on your NAT.

>  If these results are in the ballpark, what can I do to improve the =
>  situation (short of upgrading my firewall machine)?

Beyond upgrading your machine, I can't see how you can improve the
situation.  This is the physical limitation of the memory bandwidth and
processing speed of a 486 CPU.  It simply can't pass more than what it can
pass.  It has nothing to do with the NAT translation software or firewall.




To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-questions" in the body of the message




Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?00b701c04fdc$7b1afea0$aa240018>