[lug] Slow runnings on KRUD7 w/ 2.4.2 and KRUD7 router.

John Starkey jstarkey at advancecreations.com
Tue Mar 13 15:54:17 MST 2001

Thanks Dan.

Like a moron I was trying to get away with aliasing the eth0 card until I
could get an ISA NIC for my cheap 100 MHz machine with one PCI slot (the
router). The iMac was running fine so I didn't think it was the cause. I did
a traceroute and found that the packets would be ok 50% of the time and the
other tries would make it to the first remote router and come right back. The
third entry was my router in those traces. So I switched them and everything
is fine.

I guess the headers were getting crammed because of the same MAC address for
the two addies ( eth0 and eth0:1 ) one being a reserved IP. Cheapskate 101:
The Essentials: getting what you pay for.???


"D. Stimits" wrote:

> John Starkey wrote:
> >
> > I'm running two KRUD7 boxes. 1 is just routing and filtering and is a
> > stock kernel and the second is a gnome desktop running 2.4. I am also
> > viewing my work on an iMac which is routed by the first box. The iMac is
> > running usual speed consistently using all the normal net protocols.
> > But the gnome box has some very serious lag at times with all the
> > protocols. I'm in vi on a remote server and it's getting really
> > annoying. Like taking up to a minute per space when it moves, at times,
> > then 20 minutes later it will fly. The only thing I can reproduce so far
> > is when I restart it will come up fine.... then ten minutes later I'm
> > dead in the water again.
> >
> > Memory is at approx 40 percent and CPU is fine. I guess the router isn't
> > to blame since the iMac is fine. Windoze on this dual boot was fine last
> > night, while the gnome boot was lagging just before. This has been going
> > on for two days and i don't think I made any major changes, in fact i'm
> > pretty sure, same kernel, NIC (via-rhine), everything.
> >
> > Anyone know what else i could look at to track this down?
> >
> > Thanks,
> >
> > john
> >
> One minor suggestion, that probably won't be of great help. If the MTU's
> are too high on both machines, it might not be too responsive. If you
> run "ifconfig", you will see a reference to MTU, which defaults to 1500.
> This is good for internal nets and more reliable connections like T1's,
> but can really suck on a modem. For modems I tend to take a power of 2
> and add 40 to it (size of TCP headers) and get best luck with either 256
> + 40 or 512 + 40. If you do anything requiring responsiveness, you are
> probably best with 296 (256 + 40). In the case of ppp, this is done
> through an option to the pppd daemon. You can also do this with MRU, but
> MRU is only a suggestion, and can be ignored, so it tends to be less
> useful. For example, your /etc/ppp/options might have in it:
> mtu 296
> mru 556
> D. Stimits, stimits at idcomm.com
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