[Gllug] 486sx 25 machine - thoughts and comments

Ian Northeast ian at house-from-hell.demon.co.uk
Wed Apr 17 21:51:18 UTC 2002

David Cantrell wrote:
> On Fri, Apr 12, 2002 at 11:33:55PM +0100, Chris Bell wrote:
> > On Fri 12 Apr, Adrian McMenamin wrote:
> > > I have a 486sx-25 box with an adaptec scsi card and a 240mb disk (there was a
> > > 500mb disk but I have already put that in another box). The machine has some
> > > sentimental value (I've had it since 93) - as well as 32MB of memory: which
> > > was big for that time.
> > >
> > > It has an isa bus and no network card.
> > >
> > > Question is: should I chuck it or is there a real use for it?
> >    Is it fast enough for a firewall? An ISA 10baseT NIC is not difficult to
> > find, and you don't have the usual low memory problem, (computers around
> > that age often take the very short SIMMs, and you are limited to about 4MB
> > of RAM). Fit two NIC's for an ADSL ethernet to ethernet firewall? Or should
> > it be a 486DX to get sufficient speed?
> I use a DX-33 for my firewall/NAT box, and it never even breaks into a sweat.
> Considering that the difference between a 486SX and DX is only that the SX
> has no hardware floating point (as opposed to the 386DX/SX which had 32-bit
> and 16-bit data busses respectively) I'd be happy to use it as a firewall.
> You could also put a multi-port serial card in there, bung ssh on, and you
> then have a nice ssh-able terminal server.  Terminal servers are good.
> ssh-capable terminal servers are even better.

Ssh does need a bit of CPU power though. I have a 1990-ish (possibly
earlier) 386DX laptop which runs NetBSD (about the only thing it will
run, SuSE 5.2 was the only other thing I could get to work[1]) and with
the original OpenSSH from 1.5.2 it took 10 minutes to log in over ssh.
Upgrading this to (I think, it's off the net ATM due to being replaced
by a slightly less crap model) 2.9 reduced this to 1 minute. But still
rather a long time. Generating keys was a matter of going to the pub for
a couple.

I wouldn't want to allow any remote access to a firewall except ssh, so
I think that even for that you need something powerful enough to run ssh
without too much delay. I suspect your DX-33 is about the minimum. I
believe that ssh uses floating point - this is probably why my old
laptop is so slow, and if this is correct the 486SX would be too.

Regards, Ian

[1] It came with DOS/Windows 3.1, this doesn't count. Yes, I did try

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