Weird ping times

[John Pettitt]

Karan Gupta wrote:

> Hi
>   I have a router setup with fBSD
> #### uname output ########
> FreeBSD aaa.xxx.com 5.4-RELEASE FreeBSD 5.4-RELEASE #0: Wed May 25
> 15:08:04 PDT 2005     root@:/usr/src/sys/i386/compile/EFKERNEL  i386
>
> When i ping this machine from different networks i get the following
> timings
>
> [snip]
>
> Alternate good and bad times!!! I rebooted the machine to no effect.
> The problem seems to go away on its own for a few hours & then comes
> back. I ran tcpdump & saw nothing different between the times this
> behaviour was seen & the times it wasnt.
>
> The machine is running IPFW, isc-dhcp server and nat.
>
>
> Any thoughts??
>
does traceroute yield anything interesting? (from either end?) - ping
times over a second sounds like a routing problem maybe outside the machine.

I've also seen weird results with machines hat have USB serial ports on
them where the machine dies for up to 16 seconds then comes back and all
the ping packets come back at once with delays from a few ms to 16
seconds in one second steps.