Re: dst cache overflow and network freeze

Andi Kleen (ak@muc.de)
Mon, 20 Dec 1999 17:03:08 +0100


On Mon, Dec 20, 1999 at 04:51:49PM +0100, Kjartan Maraas wrote:
> Andi Kleen wrote:
> >
> > On Mon, Dec 20, 1999 at 01:42:11PM +0100, Kjartan Maraas wrote:
> > > Hi.
> > >
> > > I keep getting network freezes on 2.3.x kernels. I have a pcmcia
> > > 3Com 3CXE589DC card and a Dell Latitude. In the logs i get loads of
> > > "dst cache overflow" messages. What happens is that any existing
> > > connection ie. IRC. will continue to work, but I can't open a
> > > web page etc. fetchmail seemed to work though.
> > >
> > > from the logs:
> > >
> > > Dec 19 15:16:17 km-lt kernel: dst cache overflow
> > > Dec 19 15:16:22 km-lt kernel: dst cache overflow
> > > Dec 19 15:16:30 km-lt kernel: NET: 3 messages suppressed.
> > >
> > > Trying to telnet to a host:
> > >
> > > telnet: Unable to connect to remote host: No buffer space available
> > >
> > > The same goes for ssh.
> >
> > What does arp -na say ?
> >
>
> I will check the next time it happens
>
>
> > The usual cause is somebody running a port scan over the local network from your
> > machine. If you really want to do that you can increase the values in
> > /proc/sys/net/ipv4/neigh/gc_thresh[123]
> >
>
> Wouldn't downing the eth0 interface and/or restarting pcmia/inet/network
> stop this? The errors continued after all this.

This points to a bug.

-Andi

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